« August 2010 | Main | October 2010 »

September 2010

09/29/2010

NICOLE OR NOT, TROPICAL STORM CONDITIONS THURSDAY

The remants of tropical storm Nicole is located just south of Florida. Another area of low

pressure is developing along the stalled out frontal boundary near the

North Carolina Coast. An upper-level low is located over the Tennessee Valley. All of these

features on the playing field will promote a rather stormy time of it for us over the next 24 to 36

hours. Our brief dry spell is rapidly coming to an end as rain is already advecting rapidly

northward across Virginia and the Delmarva Peninsula this afternoon in response to diffluent

flow aloft in advance of closed upper-level low over TN Valley and developing surface low near

the Carolina Coast. An increasingly intense southerly flow, from the surface on up, will pump

northward a tremendous amount of deep, tropical moisture into our region over the next 24 to 36

hours, especially the second half of tonight into Thursday. Rain with the initial area of low

pressure, currently near the Carolina Coast, will overspread the area from south to north later

this evening. Aside from pockets of light rain this evening, the bulk of the rain should hold off

until after midnight in the city.

This area of low pressure will be near the Virginia/North Carolina border tomorrow morning with

Nicole situated off the South Carolina Coast. Precipitable water values increase dramatically late

tonight through Thursday into the 2.0 to 2.5 inch range as deeper tropical moisture gets drawn

northward. The exact center of tropical storm Nicole will become more difficult to track as it

heads northward off the East Coast tomorrow and tomorrow night as it will become elongated

and more oval shape in nature and there will be a couple of other areas of low pressure trekking

along in the flow -- basically an elongated area of low pressure will be in place along the East

Coast. In fact, most of the rain we get will have more to do with the baroclinic low developing to

our south and the fact that deep, tropical moisture will be overrunning the stalled out frontal

boundary along the East Coast and little to do with the actual entity of Nicole.

We are looking at rain much of the time tomorrow as it turns progressively windy -- stronger

winds near the coast. As of now, we are expecting 2-4 inches of rain in and around the city by

the time Friday morning rolls around, locally higher amounts of 4 or 5 inches not out of the

question. However, it appears the best moisture influx and upward motion will try to set up just

to our west and we expect the axis of heaviest rain to fall across eastern PA  and western NJ

where a general 3-6 inches of rain can fall tonight through Thursday night, locally 8 inches. We

continue to be concerned about thunderstorms with damaging wind gusts tomorrow. In fact,

there would not even have to be thunderstorms to get the damaging gusts. Models are showing

60+ knot winds at 850 mb. The trough axis will lift northeastward across the mid-Atlantic

tomorrow night, which should start to deflect some of the deeper moisture and what's left of

Nicole off to the east-northeast as the night progresses. This should lead to a tapering off trend

from west to east with the rain later tomorrow night with most of the rain over with by Friday

morning, although we are still allowing for a few lingering showers to start off Friday in case

things end up slower.

09/20/2010

AUTUMN ARRIVES WITH A WARMING TREND

AT 11:09 PM EDT WEDNESDAY EVENING, THE VERTICAL RAYS OF THE SUN FALL DIRECTLY ON THE EQUATOR. THAT EVENT, KNOWN AS THE AUTUMNAL EQUINOX, MARKS THE BEGINNING OF THE FALL SEASON IN THE NORTHERN HEMISPHERE. WE HAVE HAD A FEW FALL-LIKE DAYS SO FAR THIS MONTH, ALTHOUGH THEY HAVE GENERALLY BEEN OUTNUMBERED BY WARM, LATE SUMMER WEATHER HANGING ON. OF COURSE, WE ACTUALLY HAD SOME TRULY HOT WEATHER EARLIER IN SEPTEMBER.

A WEAK, MOISTURE-STARVED COOL FRONT THAT CROSS THE NORTHEASTERN PART OF THE COUNTRY YESTERDAY AFTERNOON AND LAST NIGHT CONTINUES TO PUSH SOUTHWARD AND AWAY FROM US. IN ITS WAKE, A DRY, VERY PLEASANT AIR MASS HAS OVERSPREAD THE REGION TODAY. HIGH PRESSURE CURRENTLY CENTERED OVER EASTERN ONTARIO WILL BUILD SOUTHEASTWARD OVER THE NEXT 24 HOURS, REACHING A POSITION OVER EASTERN PA BY TOMORROW MORNING, AND WILL THEN PUSH OFF THE MID-ATLANTIC COAST BY TOMORROW EVENING. THE AIR MASS OVER US IS QUITE DRY WITH DEW POINTS IN THE 30S AND LOW TO MID 40S OVER A LARGE AREA OF THE NORTHEAST...AWAY FROM ANY WATER INFLUENCE. WITH CLEAR SKIES AND LIGHTER WINDS TONIGHT, THE RESULT WILL BE THE COOLEST TEMPS WE HAVE EXPERIENCED SINCE SOMETIME IN MAY FOR MOST LOCATIONS. WE EVEN EXPECT AN EARLY SEASON FROST IN THE COLDEST PLACES FROM NORTHERN PA INTO UPSTATE NY AND INTERIOR NEW ENGLAND.

 TOMORROW LOOKS TO BE A BEAUTIFUL DAY WEATHER WISE FOR THE LAST FULL DAY OF SUMMER. WEDNESDAY PROMISES TO BE A WARMER DAY, THANKS TO A SOUTHWESTERLY FLOW AHEAD OF THE NEXT FRONT. IT IS INTERESTING TO NOTE THAT THE BOUNDARY LAYER ONLY EXTENDS UP TO ABOUT 950 MB THAT DAY. WE ARE GETTING INTO THAT TIME OF YEAR WHEN WE JUST CAN'T ASSUME THAT WE ARE MIXING FROM 850 MB ALL OF THE TIME. WE DEFINITELY HAVE TO CHECK THE MODEL SOUNDINGS EVERY DAY! THAT BEING SAID, WEDNESDAY DOES APPEAR TO BE A VERY WARM DAY, AND HOPEFULLY, WE ARE HIGH ENOUGH WITH OUR MAX TEMPS THAT DAY. A BAND OF MOISTURE ALONG AND AHEAD OF THE FRONTAL BOUNDARY WILL PRODUCE CLOUDS AND PERHAPS A COUPLE OF SHOWERS HERE LATE WEDNESDAY INTO WEDNESDAY NIGHT. THERE MAY EVEN BE A T-STORM IN SPOTS.

AS LONG AS THAT FRONT KEEPS ON MOVING, THEN DRY WEATHER WILL RETURN ON THURSDAY. TEMPS THAT DAY ARE VERY TRICKY, ESPECIALLY NEAR THE COAST WHERE A LIGHT PRESSURE GRADIENT MAY LEAD TO LOCAL SEA BREEZES IN THE AFTERNOON. AT THIS JUNCTURE, WE ARE LEANING TOWARD THURSDAY BEING A BIT WARMER THAN WE HAD ORIGINALLY THOUGHT. THEN, FRIDAY COULD TURN INTO A REAL "BLOW TORCH" DAY, AS SUMMER JUST DOESN'T WANT TO GIVE UP! WE TWEAKED NUMBERS UP ON FRIDAY, BUT WE STILL MAY NOT BE WARM ENOUGH. ANOTHER FRONT IS DUE TO ARRIVE HERE FRIDAY NIGHT OR SATURDAY MORNING.

09/17/2010

TORNADIC TO TRANQUIL

WHAT A DIFFERENCE A DAY MAKES! YESTERDAY WE WERE DEALING WITH ALL KINDS OF ACTIVE WEATHER ACROSS THENORTHEASTERN PART OF THE COUNTRY, INCLUDING POCKETS OF HEAVY RAIN, SOME LIGHTNING AND THUNDER, STRONG WIND GUSTS, AND EVEN SEVERE T-STORMS WITH DAMAGING WINDS. THE UPPER LEVEL TROF, AS WELL AS THE SURFACE LOW AND ITS FRONTS THAT CAUSED THE WILD WEATHER YESTERDAY CONTINUE TO MOVE AWAY TO THE EAST. IN THEIR WAKE, A DRIER AND MUCH MORE STABLE AIR MASS HAS MOVED INTO THE REGION. THIS WILL SET THE STAGE FOR A MOSTLY CLEAR, COOLER NIGHT TONIGHT AS A HIGH PRESSURE SYSTEM MOVES IN. WINDS WILL BECOME LIGHT TONIGHT, AND WITH THE MOISTURE IN THE GROUND FROM THE RECENT RAINS, WE MAY HAVE TO CONTEND WITH PATCHY FOG LATE TONIGHT INTO TOMORROW MORNING.

AFTER ANY FOG BURNS OFF TOMORROW MORNING, THE BALANCE OF THE DAY IS LOOKING GORGEOUS. HIGH PRESSURE WILL MAINTAIN CONTROL ALL DAY TOMORROW. AS A RESULT, WE EXPECT PARTLY SUNNY SKIES ALONG WITH PLEASANT TEMPS AND LIGHT WINDS.

OUR WEATHER WILL STAY QUIET AND TRANQUIL TOMORROW NIGHT. TEMPS TOMORROW NIGHT WILL COOL OFF NICELY, BUT READINGS WILL BE A TAD HIGHER THAN TONIGHT. ON SUNDAY, WE'LL BE AHEAD OF A WEAK, MOISTURE-STARVED FRONTAL SYSTEM. WITH HIGHER THICKNESSES AND 850 MB TEMPS ON SUNDAY, WE HAVE THE POTENTIAL FOR IT TO GET AT LEAST A BIT WARMER THAN TOMORROW. THE WIND FLOW ON SUNDAY WILL BE RELATIVELY WEAK, WHICH MAY KEEP TEMPS DOWN A TAD. HOWEVER, THE BIGGEST LIMITING FACTOR ON SUNDAY'S TEMPS WILL BE CLOUDS. IF THERE ARE A FAIR AMOUNT OF HIGH AND MID LEVEL CLOUDS AROUND ON SUNDAY, THEN READINGS WILL BE HELD DOWN BY AT LEAST A COUPLE OF DEGREES. WE CAN'T TOTALLY RULE OUT A BRIEF, PASSING SHOWER AT SOME POINT ON SUNDAY WITH THE ARRIVAL OF THE FRONT. HOWEVER, ODDS FAVOR IT STAYING DRY.

BEHIND THAT BOUNDARY, DRIER AND COOLER AIR WILL RETURN FOR EARLY NEXT WEEK. IT IS POSSIBLE THAT WE START MONDAY WITH LEFTOVER CLOUDINESS. HOWEVER, WE DO EXPECT THE SUN TO COME BACK OUT ON MONDAY AS DRIER AIR FROM THE NORTH WINS OUT. A GOOD SIZED HIGH PRESSURE SYSTEM WILL BE CENTERED NORTH OF THE GREAT LAKES REGION ON MONDAY MORNING. THAT HIGH WILL BUILD SOUTHEASTWARD, REACHING EASTERN PA BY TUESDAY MORNING. SO, TUESDAY IS SHAPING UP TO BE A FINE DAY WITH LOTS OF SUNSHINE. AHEAD OF THE HIGH, WE DO ANTICIPATE SOME COOLING ON MONDAY AND MONDAY NIGHT. IN FACT, IT IS POSSIBLE THAT WE ARE NOT LOW ENOUGH WITH OUR TEMPS DURING THAT PERIOD. TUESDAY COULD ALSO BE COOLER THAN WE CURRENTLY HAVE IN THE FORECAST, DEPENDING ON HOW LOW TEMPS GET MONDAY NIGHT, AND HOW STABLE THE AIR MASS REMAINS ON TUESDAY. HOWEVER, BY WEDNESDAY, WE ARE LOOKING AT A MAJOR WARMUP, AS THE HIGH PUSHES OFF THE VA OR NC COAST, TURNING OUT FLOW SOUTHWESTERLY. WE HAVE TWEAKED TEMPS UP IN MANY LOCATIONS ON WEDNESDAY, AND WE STILL MAY NOT BE WARM ENOUGH.

IN THE TROPICS, KARL MADE LANDFALL ABOUT 10 MILES NORTH OF VERA CRUZ, MEXICO AROUND 12:30 PM EDT. THAT STORM WILL CONTINUE TO BE A BIG RAINFALL PRODUCER FOR MEXICO AS IT PUSHES FARTHER INLAND.

IGOR WILL PASS VERY CLOSE TO BERMUDA SUNDAY NIGHT AS EITHER A CAT 3 OR CAT 2 HURRICANE. IGOR WILL KICK UP ROUGH SURF AND RIP CURRENTS ALONG THE EAST COAST BEACHES OF THE U.S. THIS WEEKEND AND INTO MONDAY. JULIA IS DESTINED TO JUST BE A "FISH" STORM.

09/15/2010

THUNDER THREAT THURSDAY NIGHT

Halfway through September we have only received .28" of rain and despite showers in the

forecast  tomorrow/tomorrow night, there is no real significant rain in the 5day. The surface map

this  afternoon shows a 1024 mb high centered over

the lower Great Lakes region responsible for today's nice weather.

 Meanwhile, low pressure centered over southeastern South Dakota accompanied by a cold front

slicing through the central Plains with a warm front extending into the mid-Mississippi Valley will

be our weather maker heading into Thursday night. In the short term, fairly straight-forward

weather. After a nice evening, tonight will turn out comfortably cool. The breezes of this

afternoon should diminish not long after sunset. Skies will be mainly clear, although high clouds

should sneak in from the west just before daybreak.

The bulk of the daytime hours Thursday will end up dry as clouds will be on the increase in

advance of the approaching area of low pressure which will be zipping across the Great Lakes

region in the fairly fast west to east flow set up across the northern tier of the U.S. More of a

southerly flow develops tomorrow as high pressure shifts offshore. This will pump in higher

dewpoint air. Computer models are hinting at an enhanced area of moisture convergence setting

up across the region later in the afternoon. This combined with the warm front lifting north, LI's

going negative and some CAPE, it is possible that a shower or thunderstorm breaks out later in

the afternoon, probably not until at least after 4 or 5 pm. Otherwise, the best chance for showers

will be to the west of the city with the associated storm system and lowering heights.

Low pressure will take a track well to our north tomorrow night with the trailing cold front

sweeping through during the second half of the night. The best chance for showers and

thunderstorms will come during the first half of the night in advance of this front. With the

approach of a potent vort max embedded in the shortwave trough, some instability and a 60-65

knot southwesterly low-level jet punching into the region, a stronger thunderstorm is not out of

the question with a damaging wind gust being the primary threat. Again, the main threat for this

will be during the first half of tomorrow night. When things are all said and done, we are not

looking at a tremendous amount of rain given the fast movement of this system -- probably 0.25

of an inch or less on average, although locally higher for those that get a drenching

thunderstorm. Should be dry for the Friday morning commute as dry and stable air will have

already filtered in during the second half of tomorrow night. Surface high pressure and a dry,

westerly flow aloft will promote a nice day Friday with lots of sunshine, comfortable

temperatures and a gusty northwest breeze. The nice weather should remain in place for the first

half of the weekend as high pressure holds its ground into Saturday with sunshine and near

average temperatures. Cool front approaches from the north Sunday, but moisture will be rather

limited. At this point, it looks like the bulk of the weekend will be nice.

 

09/14/2010

KARL FORMING IN THE CARIBBEAN. ANOTHER GEM TOMORROW.

ALTHOUGH THE TROPICS HAVE BEEN VERY ACTIVE FOR THE PAST FEW WEEKS, WE HAVE HAD NO CATASTROPHIC, DIRECT IMPACTS ON THE COASTS OF THE U.S. MAINLAND. SURE, WE HAVE HAD TO DEAL WITH HIGH SWELLS, ROUGH SURF, AND RIP CURRENTS ALONG THE EAST COAST, AND EARL DID BRING PRETTY GOOD RAINS TO EASTERNMOST LOCATIONS. HERMINE CAUSED VERY HEAVY RAIN AND IMPRESSIVE FLOODING TO INLAND PORTIONS OF THE SOUTHCENTRAL U.S. EARLIER IN THE SEASON, ALEX PRODUCED A DELUGE ACROSS PARTS OF SOUTH TEXAS. HOWEVER, GIVEN THE FACT THAT WE ARE NOW AT 10 NAMED STORMS FOR THE 2010 SEASON, WITH THE POTENTIAL FOR KARL TO FORM VERY SOON IN THE WESTERN CARIBBEAN, AND IN THE NOT-TOO DISTANT FUTURE - LISA, WHICH WOULD COME OFF OF AFRICA, THE PERCEPTION MAY BE THAT THIS HURRICANE SEASON REALLY HASN''T BEEN ALL THAT BAD SO FAR. IF WE CONTINUE TO HAVE "FISH" STORMS, AND SYSTEMS THAT MOVE INTO MEXICO, THEN THAT THOUGHT WILL CONTINUE, EVEN IF THE NUMBER TALLY ENDS UP RATHER HIGH.  IN ANY CASE, WE CERTAINLY WON'T HAVE TO WORRY ABOUT ANYTHING TROPICAL AROUND HERE ANYTIME SOON. BERMUDA MAY BE A DIFFERENT STORY THIS WEEKEND AS IT GEARS UP FOR IGOR.

CLOSER TO HOME, TODAY DID END UP BEING A BREEZY DAY AS WE HAD ANTICIPATED FROM YESTERDAY. A DRY, COOL NIGHT IS COMING UP, THEN TOMORROW WILL BE A DECENT DAY WEATHER WISE AS AN AREA OF HIGH PRESSURE BUILDS INTO THE NORTHEAST. TEMPS TOMORROW WILL BE SIMILAR TO TODAY, BUT PROBABLY JUST A TAD LOWER. WE STILL EXPECT A BREEZE TO BLOW AT TIMES TOMORROW, BUT IT SHOULD NOT BE QUITE AS GUSTY AS AS IT WAS TODAY.

RAINFREE CONDITIONS WILL PERSIST TOMORROW NIGHT AS THE HIGH PUSHES EASTWARD. THEN, IT DOES LOOK LIKE WE ARE IN STORE FOR A PERIOD OF WET WEATHER LATER THIS WEEK. YESTERDAY, WE WERE FACING PRETTY BIG DIFFERENCES IN THE MODELS ON THE TIMING AND ESPECIALLY THE TRACK OF THE LOW PRESSURE SYSTEM COMING EASTWARD. THERE ARE STILL SOME SUBTLE TIMING DISCREPANCIES. HOWEVER, THE MODELS HAVE ALL COME INTO LINE WITH THEIR PROJECTED TRACK...OR SHOULD WE SAY THAT THE GFS HAS COME AROUND TO THE CONSENSUS OF THE EURO, NAM, CANADIAN, ETC. WE ARE NOW LOOKING AT A MORE NORTHERLY TRACK OF THE SURFACE LOW, PUSHING THROUGH SOUTHERN MICHIGAN, UPSTATE NY, AND INTO NORTHERN NEW ENGLAND. IF THAT IS INDEED THE CASE, THEN THE BEST BATCH OF OVERRUNNING RAIN WILL PASS BY TO OUR NORTH. THE FARTHER SOUTH YOU GO, ESPECIALLY FROM NEAR THE MASON-DIXON LINE ON SOUTHWARD, THE SHORTER THE DURATION OF WARM ADVECTION RAIN THERE WILL BE, AND THE BETTER THE CHANCE IS THAT THERE WILL JUST BE A SHORT PERIOD OF SHOWERS AND PERHAPS A T-STORM WITH THE ARRIVAL OF THE COLD FRONT.

ANOTHER THING THAT LOOKS DIFFERENT TODAY, BUT ALSO COORDINATED WITH ALL OF THE MODEL SOLUTIONS, IS THAT THE LOW IS LIKELY TO KEEP MOVING RIGHT ALONG AND NOT GET HUNG UP AT ALL. THAT WOULD LEAD TO QUICKER DRIER BEHIND IT ON FRIDAY. WE DID SPEED THINGS UP SOMEWHAT FROM WHAT WE HAD OUT EARLIER, BUT WE STILL MAY BE TOO SLOW. AT THIS STAGE, THE START OF THE WEEKEND LOOKS VERY NICE ON SATURDAY.

09/13/2010

EVENING T-STORMS AND THE TROPICS

WITH SURFACE TEMPS WARMING UP NICELY TODAY, AND A COOL FRONT AND UPPER LEVEL SHORT WAVE ARRIVING FROM THE NORTHWEST, THE RESULT WAS THE DEVELOPMENT OF SCATTERED, STRONG T-STORMS THIS AFTERNOON IN PORTIONS OF UPSTATE NY, NORTHCENTRAL AND NORTHEASTERN PA, , AND VERMONT.

THERE IS CURRENTLY A SEVERE T-STORM BOX OUT FOR PARTS OF THIS AREA UNTIL 8 P.M. IT SEEMS THAT THE GREATEST THREAT IS GUSTY AND PERHAPS DAMAGING WINDS, AS WELL AS HAIL...GIVEN THE FAIRLY LOW FREEZING LEVELS. OBVIOUSLY, THE FARTHER SOUTH AND WEST YOU GO, THE LESS LIKELY IT IS TO T-STORM THIS EVENING.

AFTER THIS FEATURE GOES BY, THE ATMOSPHERE WILL SETTLE DOWN FOR THE BALANCE OF TONIGHT. MOST OR ALL OF THE TIME THE NEXT TWO DAYS LOOK DRY, AS A COUPLE OF DISTURBANCES PASS BY TO OUR NORTH. WHAT THAT MEANS HERE IS DRY, PLEASANT WEATHER, AS WE WILL BE IN A NORTHWESTERLY FLOW OF AIR. TOMORROW LOOKS QUITE BREEZY WITH A DECENT PRESSURE GRADIENT. A WELL MIXED ATMOSPHERE TOMORROW AND A NICELY ALIGNED FLOW FROM THE SURFACE ON UP WILL LEAD TO GOOD DOWNWARD TRANSFER OF MOMENTUM. FOR THAT REASON, WE EXPECT SOME WIND GUSTS TOMORROW TO BE IN THE 25 MPH RANGE...IF NOT A TAD HIGHER. TEMPS TOMORROW WILL ONLY BE ABLE TO RISE SO FAR BEFORE LEVELING OFF, AS 850 MB TEMPS DROP A BIT. HOWEVER, THERE IS SOME DEBATE AS TO JUST HOW HIGH THE TEMPS WILL GET BEFORE THEY STOP RISING.

AFTER A COMFORTABLY COOL NIGHT TOMORROW NIGHT, WEDNESDAY WILL FEATURE A GOOD DEAL OF SUNSHINE WITH AFTERNOON READINGS A LITTLE LOWER THAN TOMORROW.

LATER IN THE WEEK, THE BIGGEST FORECAST CHALLENGE IS GOING TO BE THE STRENGTH, TIMING, AND TRACK OF A SURFACE LOW HEADING EASTWARD IN THE FLOW. THE EUROPEAN, CANADIAN, AND NAM ALL WANT TO TRACK THAT SYSTEM FAIRLY FAR NORTH. HOWEVER, THE GFS HAS A MUCH FARTHER SOUTH SOLUTION, WHICH WOULD LEAD TO A DIFFERENT AREA OF OVERRUNNING RAIN, AS WELL AS COOLER TEMPS MUCH FARTHER SOUTH THAN THE OTHER MODELS. A TRACK FARTHER NORTH WOULD EVENTUALLY LEAD TO MORE CONVECTIVE TYPE OF PRECIP AND WARMER TEMPS. OF COURSE, HOW QUICKLY MOISTURE MOVES IN ON THURSDAY WILL DETERMINE HOW HIGH THE TEMPS GO THAT DAY, WITH WIND DIRECTION ALSO CRITICAL ANYWHERE NEAR A LARGER BODY OF WATER. WHAT WE CAN SAY RIGHT NOW IS THAT IT LOOKS AT LEAST SOMEWHAT UNSETTLED AND POTENTIALLY WET LATE THURSDAY INOT FRIDAY.

GOING WITH THE CURRENT TIMING OF FEATURES, IT APPEARS THAT DRY WEATHER WILL PROBABLY RETURN FOR THE UPCOMING WEEKEND.

IN THE TROPICS, "IGOR" IS A STRONG CAT 4 HURRICANE WHICH MAY EVENTUALLY THREATEN BERMUDA SOMETIME OVER THE WEEKEND.

09/07/2010

ONE MORE WARM DAY THEN A FALL PREVIEW

AS PREDICTED, TODAY TURNED OUT TO BE A VERY WARM TO HOT DAY ACROSS THE REGION, THANKS TO A NOTICEABLE UPTICK IN 850 MB TEMPS AND THICKNESSES, A DECENT AMOUNT OF SUNSHINE, AND A STIFF SOUTHWESTERLY BREEZE. IN FACT, WITH THE DRY GROUND, TEMPS IN SOME LOCATIONS OVER-ACHIEVED A BIT FROM YESTERDAY'S FORECAST.

FROM THE APPALACHIAN MOUNTAINS WESTWARD INTO THE OHIO VALLEY, AND NORTHWARD INTO UPSTATE NY AND THE EASTERN GREAT LAKES REGION, THE WARMTH WILL BE TRIMMED BACK CONSIDERABLY TOMORROW. IN FACT, IT WILL BE MUCH COOLER THE FARTHER NORTH YOU GO. EAST OF THE MOUNTAINS, HOWEVER, WE'LL SQUEAK OUT ONE MORE WARM DAY TOMORROW BEFORE A MAJOR COOL DOWN OCCURS FOR THE REMAINDER OF THE WORK WEEK. THE REASON TOMORROW WILL STILL BE A WARM DAY EAST OF THE APPALACHIANS IS DUE TO A FAIRLY HIGH LAUNCHING PAD TOMORROW MORNING, A GOOD DOWNSLOPING WESTERLY WIND, MORE SUNSHINE THAN CLOUDS DUE TO A FAST MOVING, MOISTURE-STARVED COLD FRONT, AND 850 MB TEMPS WHICH WILL BE SLUGGISH TO DROP FOR A SHORT PERIOD.

THE GFS HAS BEEN FASTEST OF THE MODELS IN COOLING THE 850 MB TEMPS TOMORROW, WHILE THE EUROPEAN HAS BEEN THE SLOWEST. IN ANY CASE, WITH FALLING HEIGHTS, COOLING ALOFT, AND SURFACE TEMPS ABOUT AS HIGH AS THEY CAN POSSIBLY GET TOMORROW, THAT WILL RESULT IN A GUSTY WIND AT TIMES, ESPECIALLY GIVEN THE WELL ALIGNED FLOW AND GOOD DOWNWARD TRANSFER OF MOMENTUM. GUSTS OF 30-35 MPH ARE A GOOD POSSIBILITY TOMORROW. ON THE ISSUE OF PRECIP WITH THE FRONTAL BOUNDARY, WE ARE VERY UNIMPRESSED WITH A WHOLE LOT HAPPENING. EVEN THIS AFTERNOON, WITH IDEAL HEATING CONDITIONS AND DEW POINTS NEAR 60 IN SOME PLACES, THE FRONT IS HAVING A TOUGH TIME GENERATING MUCH MORE THAN A FEW SCATTERED SHOWERS AND T-STORMS. THE TIMING OF THE FRONT IN OUR AREA IS VERY UNFAVORABLE, AND MOST OF THE UPPER LEVEL PASSES BY TO OUR NORTH. EVEN SO, IT DOESN'T HURT TO COVER FOR ASHOWER IN SPOTS AS THE FRONT IS IN THE VICINITY.

LOOKING AHEAD, THURSDAY AND FRIDAY WILL BE COOL, BRISK DAYS WITH TEMPS BELOW NORMAL FOR EARLY SEPTEMBER, AS WE WILL BE IN A NORTHWESTERLY FLOW AT ALL LEVELS OF THE ATMOSPHERE. TEMPS ON THURSDAY AND FRIDAY WILL BE VERY SIMILAR, AND WILL PROBABLY END UP WITHIN A DEGREE OR TWO OF EACH OTHER. WE DO EXPECT SOME INSTABILITY CLOUDS TO BE AROUND ON THURSDAY, AND THERE COULD BE A SHOWER OR TWO AS CLOSE BY AS THE POCONOS, CATSKILLS, AND THE HILLS OF NORTHWESTERN NJ.

FRIDAY WILL LIKELY BE DRY WITH A BIT MORE IN THE WAY OF SUNSHINE. AS FOR THE WEEKEND, SATURDAY WILL BE A NICE DAY WEATHER WISE, THEN IT MAY SHOWER ON SUNDAY WITH THE APPROACH OF THE NEXT FRONTAL SYSTEM. THE TIMING OF THAT FRONT IS STILL SOMEWHAT UNCERTAIN, AND THE DETAILS WILL BE WORKED OUT IN THE DAYS AHEAD.

09/06/2010

ONLY ONE CHANCE FOR WET WEATHER THIS WEEK

IF YOU LOOK AT A TEMPERATURE CURVE FOR OUR AREA, YOU'LL FIND THAT, ON AVERAGE, THE WARMEST THREE MONTHS OF THE YEAR RUN FROM EARLY JUNE TO EARLY SEPTEMBER. THIS PERIOD IS OFTEN REFERRED TO AS METEOROLOGICAL SUMMER, AND HAS NOW PRETTY MUCH COME TO AN END. THAT IS QUITE APPROPRIATE, SINCE LABOR DAY IS CONSIDERED BY MANY FOLKS TO BE THE UNOFFICIAL END TO THE SUMMER SEASON.

WE ARE NOW ENTERING METEOROLOGICAL FALL, OR THE THREE MONTHS OF THE YEAR WITH THE MOST RAPID DECLINE IN THE NORMAL TEMPS. IN FACT, FROM NOW INTO DECEMBER, THE NORMAL HIGH AND LOW DROP A DEGREE ABOUT EVERY THREE DAYS OR SO. IF YOU DON'T KEEP UP WITH THE NORMALS IN THE WEEKS AHEAD, IT IS VERY EASY TO GET OUT OF TOUCH WITH REALITY. ALSO, WITH THE SHORTENING DAYS AND LOWER SUN ANGLE, IT WILL BECOME TOUGHER AND TOUGHER FOR IT TO REACH 90 WITH EACH PASSING WEEK. THAT IS ALMOST HARD TO BELIEVE AFTER A SUMMER LIKE WE JUST HAD, WHEN READINGS ROSE INTO THE 90S AT THE DROP OF A HAT!

WE WILL PROBABLY SEE SOME 90 DEGREE PLUS TEMPS TOMORROW FROM SOUTHERN PA AND PORTIONS OF NJ ON SOUTHWARD. AREAS SOUTH OF THE MASON-DIXON LINE MAY SQUEAK OUT ANOTHER 90 DEGREE DAY ON WEDNESDAY. THAT WILL BE IT FOR 90 DEGREE WEATHER FOR AWHILE AFTER THAT. IN THE DAYS AND WEEKS AHEAD, WE WILL ALSO NOTICE A BIT DECLINE IN T-STORMS. IN FACT, IT REALLY IS GETTING TO THE POINT NOW THAT YOU REALLY NEED A STRONG TRIGGER TO GET T-STORMS TO FORM. AIR MASS T-STORMS RARELY POP UP ON THEIR OWN ANYMORE.

IN THE SHORT TERM, WE ARE LOOKING AT A FAIRLY QUICK AND NOTICEABLE WARMUP HERE DURING THE NEXT 24 HOURS. THIS WILL BE DUE TO A SHARP UPWARD SPIKE IN THICKNESSES AND 850 MB TEMPS, AND OUR SURFACE FLOW TURNING SOUTHWESTERLY AROUND THE BACKSIDE OF A DEPARTING HIGH PRESSURE SYSTEM OFF OF THE EAST COAST. OF COURSE, HAVING ENOUGH SUNSHINE HERE TOMORROW WILL DEFINITELY HELP.

TOMORROW NIGHT LOOKS RATHER WARM WITH PATCHY CLOUDS. AS A COLD FRONT ARRIVES FROM THE NORTHWEST, IT MAY TOUCH OFF A SHOWER IN SPOTS SOMETIME LATE TOMORROW NIGHT. THE FRONTAL BOUNDARY WILL CONTINUE TO PUSH SOUTHEASTWARD ON WEDNESDAY, AND MAY TRIGGER A SHOWER IN SOME LOCATIONS FROM NEW ENGLAND SOUTHWESTWARD TO THE TENNESSEE VALLEY. THE BEST TIMING OF THAT TO OCCUR ON WEDNESDAY IS IN THE MORNING, AND THE BEST CHANCE OF ANY THUNDER SEEMS TO BEFROM THE DELMARVA PENINSULA UP ACROSS THE JERSEY SHORE AND INTO SOUTHEASTERN NEW ENGLAND.

FOLLOWING THE FROPA, THURSDAY AND FRIDAY LOOK DRY AND COOLER AS WE'LL BE IN A NORTHWESTERLY FLOW OF AIR AT ALL LEVELS OF THE ATMOSPHERE. DRY WEATHER WILL PROBABLY HANG ON THROUGH SATURDAY, THEN IT MAY SHOWER AT SOME POINT DURING THE SECOND HALF OF THE WEEKEND.

IN THE MEANTIME, A DRY, COMFORTABLE NIGHT IS COMING UP. IN THE TROPICS, "HERMINE" WILL MAKE LANDFALL IN FAR NORTHEAST MEXICO THIS EVENING, NOT TOO FAR SOUTH OF BROWNSVILLE, TX. THE REMNANT LOW THAT WAS ONCE "GASTON" WILL HAVE TO BE WATCHED CAREFULLY FOR REDEVELOPMENT IN THE DAYS AHEAD.

09/01/2010

ALL ABOUT EARL

EARL IS A STRONG CAT 3 HURRICANE RIGHT NOW. BASED ON SOME OF THE FLIGHT LEVEL WINDS WE HAVE SEEN, IT IS POSSIBLE THAT IT COULD RAMP BACK UP TO A CAT 4 STORM IN THE NEAR FUTURE. EVEN IF IT DOESN'T, EARL IS A FORMIDABLE HURRICANE, AND WILL REMAIN SO FOR THE NEXT DAY OR SO.

ONCE THE STORM MAKES ITS TURN TO THE NORTHEAST ON FRIDAY, ITS FORWARD SPEED WILL REALLY ACCELERATE. THE SAME FACTORS THAT WE HAVE BEEN COVERING THE PAST COUPLE OF DAYS ARE STILL IN PLAY AS WE GO FORWARD. AS FOR THE INTERACTION WITH THE APPROACHING UPPER LEVEL TROF, IT SEEMS LIKE IT WILL ACT LIKE MORE OF A KICKER, RATHER THAN PULLING EARL INTO THE TROF. THERE IS PRETTY DECENT CONSENSUS WITH THE VARIOUS MODEL SOLUTIONS, ALTHOUGH THERE ARE STILL A COUPLE OF OUTLIERS, SUCH AS THE NAVY NOGAPS. THAT MODEL BRINGS EARL RIGHT UP ACROSS CAPE HATTERAS, AND THEN UP THE COAST, EVENTUALLY CROSSING LONG ISLAND AND HEADING TOWARD BOSTON. AGAIN, THIS IS AN ODDBALL SOLUTION, AND WE ARE NOT BUYING IT. BASED ON THE LATEST INFORMATION WE HAVE, HERE ARE SOME SPECIFICS OF WHAT WE EXPECT...

EARL WILL MAKE ITS CLOSEST APPROACH TO CAPE HATTERAS TOMORROW NIGHT, PROBABLY AROUND MIDNIGHT. AT THAT POINT, THE STORM WILL BE 60-80 MILES EAST OF HATTERAS. IT WILL MAKE ITS CLOSEST SWIPE TO CAPE COD LATE FRIDAY NIGHT OR EARLY SATURDAY MORNING. ONCE AGAIN, WE ARE PROBABLY LOOKING AT A CLOSEST APPROACH OF 60-80 MILES. SO, YOU CAN SAY THAT THIS IS A "CAPE TO CAPE" STORM, BUT STAYING JUST OFFSHORE. HURRICANE FORCE WINDS EXTEND OUT TO ABOUT 90 MILES TO THE EAST OF THE STORM CENTER, AND ABOUT 60 MILES TO THE WEST OF THE CENTER. THAT IS THE AVERAGE, AND AS THE HURRICANE WOBBLES FROM TIME TO TIME, THAT ORIENTATION COULD BRIEFLY CHANGE. SO, IF YOU DO THE MATH, YOU CAN SEE THAT THE OUTER BANKS OF NC COULD GET SOME HURRICANE FORCE WIND GUSTS, AND THE SAME THING CAN HAPPEN ON NANTUCKET ISLAND AND OUTER CAPE COD. IN THIS KIND OF STORM, WIND SPEEDS GENERALLY DROP OFF FAIRLY QUICKLY TO THE WEST. BY THE TIME YOU GET BACK TO THE I-95 CORRIDOR FROM NYC TO PHL, PEAK GUSTS MAY BE ON THE ORDER OF 30-35 MPH, WITH A FURTHER DROP OFF TO THE WEST.

HIGHEST WAVE HEIGHTS ALONG THE MD, DE, NJ, AND MOST OF THE LONG ISLAND BEACHES WILL BE IN THE RANGE OF 8-12 FEET. OUT NEAR MONTAUK POINT, WAVE HEIGHTS COULD BE IN THE 12-15 FEET RANGE, WITH 15-20+ FOOT WAVES OUT AT NANTUCKET. RIP CURRENTS AND VERY ROUGH SURF WILL BE A HUGE PROBLEM ALL UP AND DOWN THE EAST COAST. IN ALL LIKELIHOOD, MOST BEACHES WILL BE CLOSED FOR A PERIOD OF TIME, I.E., NOBODY WILL BE ALLOWED IN THE WATER.

AS FOR RAIN, WE ARE STILL LOOKING A VERY TIGHT GRADIENT FROM EAST TO WEST WITH THIS STORM, GIVEN THE STRONG SUBSIDENCE ZONE THAT WILL BE SETTING UP BETWEEN EARL AND THE COLD FRONT TO THE WEST. THE EASTERN TIP OF LONG ISLAND MAY END UP WITH 3" OR MORE OF RAIN, WHILE AREAS NOT TOO FAR WEST OF NYC END UP WITH NOT EVEN A DROP. WE STILL BELIEVE THAT IN THAT NARROW STRIP BETWEEN EARL'S MOISTURE AND THE CLOUDS AND SHOWERS WITH THE APPROACHING COLD FRONT, TEMPS COULD REALLY OVER-ACHIEVE WITH ENOUGH SUN, GIVEN HOW HIGH THE 850MB TEMPS WILL BE ON FRIDAY. THAT ZONE WILL STRETCH FROM PARTS OF VA UP TOWARD BINGHAMTON, NY. MUCH, MUCH COOLER WEATHER IS ON THE WAY FOR THIS WEEKEND.