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September 2009

09/25/2009

50/50 WEEKEND

THE COOL, LOW DEW POINT AIR MADE NICE PROGRESS SOUTHWARD LATE LAST NIGHT AND TODAY. YOU CAN STILL SEE THE DRIER AIR PUSHING SOUTHWARD AS OF THIS WRITING, JUST BY TAKING A QUICK GLANCE AT THE LATEST SATELLITE LOOP. THAT TREND WILL SOON COME TO A HALT AS THE FRONT STALLS. THEN, MOISTURE WILL BEGIN TO RETURN TO THE NORTH AND EAST, IN RESPONSE TO A DEVELOPING OVERRUNNING SITUATION. I AM STILL VERY CONFIDENT THAT TOMORROW WILL REMAIN DRY ACROSS MOST, IF NOT ALL, OF THE COVERAGE AREA. THE EXCEPTION TO THAT MAY BE THE FAR WESTERN PORTIONS OF THE REGION, NEAR THE DELAWARE RIVER, WHERE A LITTLE RAIN MAY SNEAK IN BY SUPPER TIME TOMORROW. ELSEWHERE, TOMORROW WILL BE A DRY, BUT COOL DAY WITH SUN GIVING WAY TO INCREASING CLOUDINESS.

AFTER BEING WAY FAR APART YESTERDAY AT THIS TIME, THE COMPUTER MODELS ARE MUCH CLOSER IN THEIR SOLUTIONS ON THE TIMING OF THE RAIN. IT APPEARS THAT RAIN WILL OVERSPREAD THE AREA TOMORROW NIGHT, AND THEN CONTINUE INTO OR THROUGH SUNDAY MORNING. THERE COULD BE A FEW HEAVIER BOUTS OF RAIN DURING THAT TIME. THE MOST LIKELY RAINFALL TOTALS WILL BE 1/2 TO 1 INCH, WITH THE CHANCE THAT SOME PLACES GET AS MUCH AS 1.5". AS FOR SUNDAY, ALL OF THE MODELS, TO SOME DEGREE OR ANOTHER, ARE SHOWING A TRIPLE POINT LOW DEVELOPING, AND THEN RUNNING OFF OF THE EAST COAST. THAT WILL LIKELY OCCUR SOMEWHERE BETWEEN NYC AND CAPE MAY, NJ. THE MORNING DEFINITELY LOOKS WET HERE. GIVEN THE POSITION OF THAT SURFACE LOW, AND ALSO THE UPPER LEVEL TROF AXIS, SOME RAIN, OR SHOWERS, COULD PERSIST INTO THE EARLY AFTERNOON HOURS.THAT ALMOST CERTAINLY WILL HAPPEN EAST OF THE CITY. ALSO, WITH THE TRIPLE POINT LOW LIKELY EXITING SOUTH OF THE CITY, THE LOW LEVELS MAY TEND TO STAY RATHER MOIST WELL INTO SUNDAY AFTERNOON, DESPITE THE DRYING THAT OCCURS ALOFT. THAT WOULD MEAN THAT ANY CLEARING JUST EAST AND NORTHEAST OF THE CITY MAY NOT HAPPEN AT ALL. OF COURSE, THAT ALL HAS A BEARING ON HOW HIGH THE TEMPS GO THAT DAY.

THE REMAINDER OF THE FORECAST LOOKS GOOD FROM EARLIER CONTINUITY. MONDAY WILL BE A BREEZY, FAIRLY WARM DAY AHEAD OF THAT NEXT COLD FRONT. A LINE OF GUSTY SHOWERS AND T-STORMS WILL ARRIVE FROM THE WEST SOMETIME DURING THE P.M. OR EVENING HOURS. FOLLOWING THE FRONTAL PASSAGE, GUSTY WEST TO NORTHWEST WINDS WILL USHER IN A VERY COOL AIR MASS FOR THE MIDDLE OF NEXT WEEK.

09/24/2009

Back to Reality

A COOL FRONT CONTINUES TO SLOWLY BUT SURELY PRESS SOUTH OF THE TRI-STATE AREA. HOWEVER, IT IS CURRENTLY BEING HELD UP BY A LOW PRESSURE WAVE THAT IS LOCATED OUT IN THE LOWER OHIO VALLEY. THAT FEATURE WILL KEEP PLENTY OF CLOUDS IN AREAS SOUTH OF OUR REGIONTONIGHT INTO TOMORROW MORNING.IN ADDITION, WE EXPECT SOME RAIN LATE TONIGHT INTO PART OF TOMORROW IN AREAS MAINLY SOUTH OF THE MASON-DIXON LINE, AND PERHAPS SOUTH OF WASHINGTON, DC.

MEANWHILE, DRIER AIR WILL CONTINUE TO MAKE INROADS INTO NORTHERN PA, SOUTHERN NY STATE, SOUTHERN NEW ENGLAND WITH SKIES TURNING OUTMOSTLY CLEAR TONIGHT. ONCE THE DISTURBANCE ON THE FRONTAL BOUNDARY MOVES BY, THAT WILL ALLOW THE UPPER LEVEL RIDGE TO BUILD JUST TO OUR WEST. THAT, IN TURN, WILL CAUSE THE SURFACE HIGH TO BUILD SOUTHWARD, BRINGING ITS DRIER, LOW DEW POINT AIR MASS WITH IT. AS A RESULT, TOMORROW IS LIKELY TO BE A REALLY NICE DAY WEATHER WISE HERE WITH A FAIR AMOUNT OF SUNSHINE, BUT ALSO A COOL NORTH TO NORTHEAST BREEZE.

DRY, COOL CONDITIONS WILL BE THE RULE TOMORROW NIGHT INTO SATURDAY. HOWEVER, BY SATURDAY AFTERNOON, I DO EXPECT MOISTURE TO RETURN FROM THE WEST AS THE UPPER LEVEL LOW THAT HAS BEEN OUT IN THE MIDWEST FOR DAYS FINALLY BEGINS TO MOVE EASTWARD. THAT WILL LEAD TO AN INCREASE IN CLOUDINESS HERE, FOLLOWED BY SOME RAIN. THERE IS STILL A HUGE DISCREPANCY IN TIMING OF THE RAIN THIS WEEKEND BETWEEN THE COMPUTER MODELS. AT THIS POINT, I PREFER SOME SORT OF COMPROMISE SOLUTION, WITH PERHAPS A LEAN TOWARD THE FASTER SOLUTION. OF COURSE, THE FASTER IT MOISTENS UP HERE ON SATURDAY, THE COOLER IT WILL END UP BEING. THE WEEKEND SYSTEM COULD END UP BEING FULL OF MOISTURE, AND THAT WOULD MEAN A GOOD SOAKING RAIN HERE. AN INCH OF RAIN OR MORE IS DEFINITELY WITHIN THE REALM OF POSSIBILITY, WITH THE POTENTIAL FOR 2 INCHES OR MORE. SHOWERS OR STEADY RAIN WILL LINGER FOR AWHILE ON SUNDAY, BUT THE TREND THAT DAY WILL BE FOR DRIER AIR TO MOVE IN FROM THE WEST BY THE AFTERNOON HOURS. THAT WILL ALSO MEAN SLIGHTLY WARMER TEMPS. LOOKING AHEAD, THE NEXT COLD FRONT IS DUE TO ARRIVE HERE LATE MONDAY AFTERNOON OR EVENING. THAT WILL PROBABLY BE ACCOMPANIED BY A SHOWER OR T-STORM, AND IT WILL BE FOLLOWED BY A SHOT OF PRETTY COOL AIR FOR THE MIDDLE OF NEXT WEEK.

Forecast Discussion:

 

 

09/22/2009

STICKY START TO FALL

FALL OFFICIALLY ARRIVED AT 5:18 P.M. THIS EVENING, WITH TOMORROW BEING THE FIRST FULL DAY OF FALL. DESPITE THAT FACT, IT ACTUALLY LOOKS LIKE THE BEGINNING OF AUTUMN 2009 WILL BE MORE LIKE SUMMER. TEMPS THROUGH THURSDAY WILL AVERAGE WARMER THAN NORMAL, AND WE WILL CERTAINLY BE DEALING WITH SOME OF THE HIGHEST DEW POINTS WE HAVE HAD HERE ALL MONTH. WITH THE HUMID AIR IN PLACE FOR THE NEXT COUPLE OF DAYS,WE WILL ALSO BE DEALING WITH A FAIR AMOUNT OF CLOUDINESS, AND AT TIMES A SHOWER OR T-STORM. WHILE MUCH OF THE TIME THROUGH THURSDAY WILL BE RAINFREE, AND MOST OF THE RAIN THAT FALLS HERE OVER THE NEXT 48 HOURS WILL BE ON THE LIGHT SIDE, WE CERTAINLY DO HAVE TO BE ON GUARD FOR A BRIEF DOWNPOUR IN SOME PLACES, GIVEN THE HIGH DEW POINTS.

PROBABLY THE MOST CHALLENGING PART OF OUR FORECAST THROUGH THURSDAY IS FIGURING OUT EXACTLY WHEN IT IS GOING TO SHOWER HERE. A COLD FRONT WILL ARRIVE THURSDAY MIDDAY. THE FRONT WILL BRING AN END TO THE SHOWER THREAT AND IF THE SUN COMES OUT BY LUNCHTIME, TEMPERATURES WILL CLOSE TO 80 DEGREES IN THE AFTERNOON. BEHIND THAT FRONTAL BOUNDARY, A BIG HIGH PRESSURE SYSTEM WILL BUILD INTO THE NORTHEAST ON FRIDAY. THE RESULT WILL BE A RETURN TO MOSTLY SUNNY WEATHER HERE WITH MUCH LOWER DEW POINTS AS WELL AS COOLER TEMPS.

THAT HIGH WILL SLIDE OFF OF THE NEW ENGLAND COAST ON SATURDAY, WHICH WILL OPEN THE DOOR FOR MOISTURE TO RETURN FROM THE WEST. JUST HOW QUICKLY THAT HAPPENS WILL DEPEND ON WHAT HAPPENS WITH THE UPPER LEVEL CLOSED LOW OUT TO OUR WEST OVER THE NATION'S MID-SECTION. THE LONGER IT TAKES FOR THAT SYSTEM TO OPEN UP AND BEGIN PUSHING EASTWARD, THE LONGER THE DRY WEATHER WILL HOLD ON HERE. OF COURSE, IF THE UPPER LOW OPENS UP FASTER THAN WE ARE NOW BARGAINING FOR, THEN CLOUDS AND WET WEATHER COULD BE MOVING IN AT A MORE RAPID PACE, PERHAPS AS EARLY AS SATURDAY EVENING. THAT IS SOMETHING WE WILL HAVE TO WATCH CAREFULLY FOR THE REMAINDER OF THE WORK WEEK AND ADJUST ACCORDINGLY. EITHER WAY, I HAVE MADE SOME DOWNWARD TWEAKS IN OUR FORECAST TEMPS FOR FRIDAY AND SATURDAY, AND I STILL MAYNOT BE COOL ENOUGH. THAT AIR MASS LOOKS PRETTY COOL IN THE LOW LEVELS, DESPITE THE HIGH HEIGHT FIELD OVERHEAD. THE SECOND HALF OF THE WEEKEND WILL LIKELY BE UNSETTLED HERE WITH THE CHANCE OF SHOWERS AND A T-STORM ON SUNDAY.

09/21/2009

Calendar says fall, but the weather says summer

AT 5:18 P.M. TOMORROW, THE EXACT VERTICAL RAYS OF THE SUN FALL ON THE EQUATOR. THISEVENT, KNOWN AS THE AUTUMNAL EQUINOX, MARKS THE BEGINNING OF THE FALL SEASON IN THE NORTHERN HEMISPHERE. EVEN THOUGH NORMALTEMPERATURES HAVE BEEN TRENDING DOWNWARD FOR AWHILE NOW AND WE HAVE ALREADY HAD A COUPLE OF TASTES OF FALL-LIKE CONDITIONS, WE STILL HAVE A LONG WAY TO GO. HOWEVER, DESPITE THE ARRIVAL OF FALL TOMORROW, IT APPEARS THAT TEMPERATURES MUCH OF THIS WEEK WILL AVERAGE ON THEWARM SIDE OF NORMAL, AS SUMMER WEATHER TRIES TO HANG ON A LITTLE LONGER. WE WILL REMAIN IN A HEIGHT, FAIRLY HIGH THICKNESS, AND WARM 850 MB TEMPERATURE REGIME THROUGH THURSDAY OR THURSDAY NIGHT.

SOME COOLING IS LIKELY AT THE END OF THE WEEK AND INTO THE START OF THE WEEKEND. HOWEVER, JUST HOW COOL WE GET THEN WILL DEPEND ON THE STRENGTH OF THE NEXTHIGH BUILDING DOWN OUT OF CANADA. OF COURSE, THE SOURCE REGION OF THAT LATE WEEK AIR MASS WILL ALSO PLAY A KEY ROLE IN HOW MUCH COOLING WE GET HERE. AT THIS POINT, IT LOOKS SIMILAR TO OR SLIGHTLY LESS COOL THAN THE AIR MASS WE DEALT WITH THIS PAST WEEKEND.

AS FOR WHICH DAY THIS WEEK WILL BE OUR WARMEST, IT WILL PROBABLY BE THURSDAY, AHEAD OF THAT LATE-WEEK FRONTALSYSTEM. AS FOR RAIN THIS WEEK, IT APPEARS THAT THE BOTH THE UPPER LEVEL RIDGE AND THE SURFACE HIGH DEPARTING OFF OF THE EASTCOAST WILL WANT TO KEEP THE SHOWERSAT BAY FOR A LITTLE WHILE LONGER. MOST OF THE MOISTURE WILL BE AIMED NORTHEASTWARD IN THE FLOW, IN CONJUNCTION WITH A COUPLE OF QUICK MOVING SHORT WAVES. THIS ZONE WILL ENCOMPASS THE AREA FROM THE APPALACHIAN MOUNTAINS WESTWARD INTO THE GREAT LAKES AND OHIO VALLEY. EVENTUALLY, THE AREA OF CLOUDS AND SHOWERS WILL SHIFT FARTHER EASTWARD LATE TOMORROW, AND ESPECIALLY TOMORROW NIGHT INTO WEDNESDAY. WHILE RAINFALL AMOUNTS WITH THIS SETUP WILL GENERALLY BE ON THE LIGHT SIDE, THAT IS NOT TO SAY THAT SOME PLACES CAN'T GET A BRIEF DOWNPOUR, DUE TO A VERY NOTICEABLE UPTICK IN DEW POINTS AROUND HERE OVER THE NEXT COUPLE OF DAYS. IN FACT, IT HAS BEEN AWHILE SINCE IT HAS FELT TRULY HUMID, BUT THAT IS ABOUT TO CHANGE PRETTY SOON. LOOKING AHEAD, CLOUDS WILL PROBABLY WIN OUT OVER SUNSHINE ON THURSDAY, AND WE CAN'T RULE OUT A SHOWER OR T-SHOWER. THE COOL FRONT WILL ARRIVE SOMETIME THURSDAY NIGHT, FOLLOWED BY A RETURN OF DRY WEATHER FOR FRIDAY AND SATURDAY AS HIGH PRESSURE BUILDS BACK IN.

09/16/2009

Autumn is in the Air

COASTAL FLOOD ADVISORY THROUGH NOON TOMORROW

A COLD FRONT HAS PUSHED TO OUR SOUTH  AND WILL CONTINUE TO PRESS SOUTHWARD SOME MORE DURING THE NEXT 24 HOURS. EVENTUALLY, THE FRONT GETS WEDGED DOWN INTO SOUTHERN NC. AT THE SAME TIME, A BIG SURFACE HIGH NOW UP NORTH IN WESTERN QUEBEC WILL BUILD SOUTHEASTWARD TONIGHT AND TOMORROW. THE NET RESULT WILL BE AN EAST TO NORTHEAST FLOW IN THE LOW LEVELS OF THE ATMOSPHERE INTO TOMORROW, KEEPING A FAIR AMOUNT OF MOISTURE AROUND.

AS FOR THE UPPER AIR PATTERN, A FAIRLY HEALTHY LOOKING TROUGH, OR DIP IN THE JET STREAM,  IS MOVING INTO THE NORTHEAST NOW. THAT FEATURE WILL STRENGTHEN  SOMEWHAT TOMORROW AN D WILL HEAD SOUTHWARD IN THE FLOW TOMORROW P.M. AND NIGHT. BY FRIDAY, THAT SYSTEM WILL BE LONG GONE. WHAT THIS ALL BOILS DOWN TO FOR US IS A PERIOD OF MOSTLY CLOUDY WEATHER TONIGHT TONIGHT INTO TOMORROW. A BIT OF RAIN WILL FALL IN PARTS OF THE REGION, PRIMARILY SOUTH AND WEST OF THE CITY. HOWEVER, THIS IS A TRICKY SITUATION AND WE HAVE TO WATCH THE PROGRESSION ON RADAR VERY CLOSELY. RAINFALL TOTALS IN THE PLACES WHERE IT DOES RAIN ARE LIKELY TO BE ON THE LIGHT SIDE...PROBABLY ON THE ORDER OF UNDER 1/4", AND MAYBE AS LITTLE AS A FEW HUNDREDTHS OF AN INCH. IF IT ENDS UP BEING CLOUDY ALL DAY TOMORROW WITH AN EASTERLY FLOW AND A BIT OF RAIN, THEN TEMPS WILL BE HELD TO COOLER LEVELS THAN WHAT I AM FORECASTING. HOWEVER, IF CLOUDS ARE ABLE TO BREAK FOR SOME P.M. SUN, THEN MY NUMBERS ARE FINE.

FRIDAY WILL BE A DRY DAY WITH MORE OF A WESTERLY FLOW AHEAD OF THE NEXT COLD FRONT. THAT WILL LEAD TO SOME SUNSHINE AND A WARMER AFTERNOON. THE FRONT WILL CROSS OUR AREA IN AN UNEVENTFUL FASHION FRIDAY NIGHT. FOLLOWING THE FRONT, THE WEEKEND WILL BE DRY AND COMFORTABLE, WITH SATURDAY NIGHT BECOMING QUITE COOL. IN FACT, THERE MAY EVEN BE A TOUCH OF FROST SATURDAY NIGHT IN PARTS OF EASTERN NY STATE AND INTERIOR NEW ENGLAND.