279  
FXUS61 KOKX 200221  
AFDOKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW YORK NY  
1021 PM EDT SUN OCT 19 2014  
   
SYNOPSIS
 
 
HIGH PRESSURE BUILDS TO THE SOUTH TONIGHT AND THEN OFF THE MID  
ATLANTIC COAST ON MONDAY, LOW PRESSURE WILL THEN APPROACH FROM  
THE GREAT LAKES MONDAY NIGHT. SECONDARY LOW PRESSURE DEVELOPS  
NEAR THE MID-ATLANTIC COAST BY LATE TUESDAY...THEN SLOWLY MEANDERS  
TO THE GULF OF MAINE BY FRIDAY MORNING...THEN TO THE CANADIAN  
MARITIME PROVINCES BY SATURDAY MORNING. A COLD FRONT APPROACHES  
FROM THE NORTHWEST SATURDAY...THEN CROSSES THE AREA SATURDAY  
NIGHT. HIGH PRESSURE BUILDS IN FROM SOUTH CENTRAL CANADA SUNDAY.  
 

 
   
NEAR TERM /THROUGH MONDAY/
 
 
MINOR ADJUSTMENTS MADE TO TEMPS...DEWPOINTS...AND CLOUD COVERAGE  
IN THE FORECAST DATABASE TO BETTER MATCH OBSERVED TRENDS. THE  
FORECAST OVERALL IS ON TRACK WITH MOST FORECAST TEMPERATURES  
WITHIN A FEW DEGREES OF OBSERVED VALUES SO FAR TONIGHT. WINDS ARE  
STAYING UP A LITTLE LONGER BUT THE LIGHT WINDS ARE PRESENT NOW  
ACROSS LOCATIONS NORTH AND WEST OF NYC...WITH LOCATIONS CLOSER TO  
THE CITY AND ALONG THE COAST GETTING LOWER WINDS AS WELL BY THE  
OVERNIGHT PERIOD.  
 
MEAN TROF RESIDES ACROSS THE EASTERN U.S. AS IT ONCE AGAIN WILL  
RELOAD WITH SHORT WAVE ENERGY ACROSS THE UPPER MIDWEST...CARVING  
OUT ANOTHER AMPLIFIED TROF ACROSS THE GREAT LAKES AND OHIO VALLEY  
STATES BY MON NIGHT. PRIOR TO THAT TIME...RIDGING BOTH ALOFT AND AT  
THE SFC MOVES INTO THE AREA TONIGHT. GUSTY NW WINDS EARLY THIS  
EVENING WILL FALL OFF QUICKLY.  
 
THE COMBINATION OF A LIGHT W/NW FLOW OVERNIGHT...MAINLY CLEAR  
SKIES...AND A DRY AIR MASS WILL ALLOW INTERIOR LOCATIONS TO DROP  
TO AROUND FREEZING AND MOST OTHER LOCATIONS OUTSIDE OF METRO NY  
INTO THE UPPER 30S. FREEZE WARNINGS AND FROST ADVISORIES REMAIN UP  
FOR MOST LOCATIONS WITH THE EXCEPTION OF NYC METRO AND WESTERN LI.  
THE AVERAGE FIRST AUTUMN FREEZE IS OCTOBER 21 FOR THE INTERIOR...SO  
THIS RIGHT ON TIME FROM A CLIMATOLOGICAL PERSPECTIVE. MOST LOCATIONS  
WILL BE ABOUT 5 TO 10 DEGREES BELOW NORMAL. THERE ARE THOUGH A  
COUPLE OF LIMITING FACTORS THAT WILL HAVE TO BE WATCHED OVERNIGHT  
WITH THE POTENTIAL FOR HIGH CLOUDS TO MOVE IN FROM THE MIDWEST AND  
THE AIR MASS PERHAPS BEING JUST DRY ENOUGH TO LIMIT FROST  
FORMATION.  
 

 
   
SHORT TERM /MONDAY NIGHT/
 
 
HIGH PRESSURE WILL MOVE OFF THE MID ATLANTIC COAST ON MON WITH A  
RETURN SW FLOW...WHILE LOW PRESSURE DROPS SE ACROSS THE GREAT  
LAKES. THERE IS SOME UNCERTAINTY WITH THE OPAQUENESS OF THE MID AND  
HIGH LEVEL CLOUDS AND THE AMOUNT OF SUN FILTERING THROUGH.  
CONDITIONS WILL LIKELY START OFF PARTLY TO MOSTLY SUNNY...BUT  
BECOME MOSTLY CLOUDY LATE AS MID LEVEL CLOUDS FILTER IN FROM THE  
WEST. HIGHS ON MON WILL BE A TOUCH WARMER WITH A SW FLOW...BUT A  
SUBSIDENCE INVERSION WILL INHIBIT DEEP MIXING...WITH HIGH ONLY IN  
THE MID AND UPPER 50S.  
 
FOR MON NIGHT...WEAK LIFT AND DEEPENING MOISTURE MAY RESULT IN  
SOME SHOWER ACTIVITY AFTER MIDNIGHT. RAINFALL AMOUNTS WILL BE  
LIGHT. HEIGHTS BEGIN TO FALL LATE AT NIGHT IN RESPONSE TO THE  
APPROACHING LONGWAVE TROF TO THE WEST.  
 
LOWS WILL BE CONSIDERABLY WARMER DUE TO THE CLOUD COVER AND SW  
FLOW...WITH MOST LOCATIONS 45 TO 50.  
 

 
   
LONG TERM /TUESDAY THROUGH SUNDAY/
 
 
MODELS START OUT IN SOLID AGREEMENT ON OVERALL PATTERN...AND MOST  
DETAILS ON TUESDAY...BUT THEN BEGIN TO DIVERGE LATTER IN THE  
WEEK...ESPECIALLY ON THE HANDLING OF SYSTEMS TO THE WEST OF THE  
CUTOFF LOW THAT EXITS TO OUR NORTHEAST LATE THIS WEEK. USED A BLEND  
OF ALL AVAILABLE GUIDANCE THROUGH FRIDAY NIGHT...THEN LEANED TOWARDS  
THE ECMWF FOR SATURDAY THROUGH SUNDAY. I USED THIS BLEND LATE IN THE  
PERIOD DUE TO THE ECMWF BETTER RUN TO RUN CONSISTENCY...THE GEFS  
ENSEMBLES SUPPORTING A LESS PROGRESSIVE PATTERN...ESPECIALLY WITH  
REGARDS TO THE LARGE AMPLITUDE RIDGE TO OUR WEST...AND BETTER  
HISTORICAL VERIFICATION OF THE ECMWF IN THIS TIME FRAME.  
 
THE WEATHER WILL BE UNSETTLED FROM TUESDAY INTO AT LEAST FRIDAY AS A  
CUTOFF LOW INITIALLY TRACKS TO OUR S...THEN MEANDERS NEAR US DURING  
THE MIDDLE OF THE WEEK...THEN SLOWLY LIFTS TO THE NORTHEAST TO THE  
CANADIAN MARITIMES BY THE WEEKEND. HOWEVER...WITH THE CUTOFF LOW SO  
CLOSE TO THE REGION...WOULD NOT EXPECT CONTINUOUS PRECIPITATION  
DURING THIS TIME FRAME. ISENTROPIC LIFT OF ANY SIGNIFICANCE APPEARS  
TO HOLD OFF UNTIL TUESDAY NIGHT...SO ONLY FORECASTING A CHANCE OF  
SHOWERS ON TUESDAY - EXCEPT LIKELY W 1/3 OF CWA CLOSER TO CLOSED  
LOW. THEN HAVE RAIN LIKELY TUESDAY NIGHT-WEDNESDAY IN RESPONSE TO  
DECENT ISENTROPIC LIFT - ULTIMATELY WILL LIKELY END UP BEING PERIODS  
OF RAIN IN THIS TIME FRAME...LINGERING LIKELY POPS INTO WEDNESDAY  
NIGHT AS BEST ISENTROPIC LIFT TRANSITIONS EAST WITH FORECAST TRACK  
OF SURFACE LOW. HAVE LIKELY POPS ON THURSDAY ACROSS NORTHERN ZONE IN  
RESPONSE TO LIKELY LOCATION OF DEFORMATION AXIS AS CLOSED LOW BEGINS  
TO LIFT TO THE NE. THEN LINGER CHANCE POPS INTO FRIDAY AS THE LOW  
LIFTS FARTHER NE.  
 
FOR NOW GOING DRY FRIDAY NIGHT-SUNDAY...AS APPEARS WILL BE LIMITED  
LOW LEVEL MOISTURE AVAILABLE FOR PASSING COLD FRONT/NORTHERN STREAM  
TROUGH TO ACT ON SATURDAY NIGHT...WITH WEAK RIDGING AHEAD OF THE  
TROUGH. SHOULD THEN HAVE A DRY NW FLOW ON THE BACKSIDE OF THE  
TROUGH.  
 
FOR HIGHS ON TUESDAY USED A BLEND OF MAV/MET/ECS GUIDANCE WITH NAM  
2-METER TEMPERATURES AND A MIX DOWN FROM 925-875 HPA PER BUFKIT  
SOUNDINGS. EXPECT HIGHS TO BE NEAR TO SLIGHTLY ABOVE NORMAL. A BLEND  
OF MAV AND MET GUIDANCE WITH NAM 2-METER TEMPERATURES WAS USED FOR  
LOWS TUESDAY NIGHT WITH READINGS FORECAST TO BE 5 TO 10 DEGREES  
ABOVE NORMAL. ON WEDNESDAY A BLEND OF MEX/MEN/EKD/ECE/ECM/WPC  
GUIDANCE WITH NAM 2-METER TEMPERATURES AND A MIX DOWN FROM 950 HPA  
PER BUFKIT SOUNDINGS WAS USED FOR HIGHS. EXPECT VALUES TO BE AROUND  
5 DEGREES BELOW NORMAL.  
 
FROM WEDNESDAY NIGHT THROUGH SUNDAY A BLEND OF  
MEX/MEN/EKD/ECE/ECM/WPC GUIDANCE WAS USED FOR TEMPERATURES. LOWS  
WILL RUN SLIGHTLY ABOVE NORMAL IN THIS TIME FRAME...AND AFTER  
SLIGHTLY BELOW NORMAL HIGHS ON THURSDAY...HIGHS WILL RUN NEAR TO  
SLIGHTLY ABOVE NORMAL AS WELL FRIDAY THROUGH SUNDAY.  
 
IT SHOULD BE NOTED THAT HIGHS ON SUNDAY COULD END UP BEING SOME 5-10  
DEGREES COLDER THAN FORECAST IF THE ECMWF VERIFIES - IN RESPONSE TO  
SHALLOW LOW LEVEL COLD ADVECTION BEHIND THE COLD FRONT.  
 

 
   
AVIATION /03Z MONDAY THROUGH FRIDAY/
 
 
HIGH PRESSURE OVER THE TERMINALS REMAINS THROUGH THE OVERNIGHT  
AND THEN MOVES OFF THE MID ATLANTIC COAST MONDAY MORNING. LOW  
PRESSURE APPROACHES FROM THE NORTHWEST MONDAY AFTERNOON WITH A  
WARM FRONT MOVING THROUGH LATE IN THE DAY.  
 
VFR. THERE COULD BE SOME SPRINKLES WEST OF THE TERMINALS LATE IN  
THE DAY.  
 
NORTHWEST WIND LESS THAN 10 KT BACKS TO WEST OVERNIGHT. THE WIND  
CONTINUES TO BACK TO THE SOUTHWEST MONDAY MORNING AND THEN WILL BE  
NEARLY SOUTHERLY LATE IN THE AFTERNOON. SPEEDS INCREASE TO AROUND  
10 KT DURING THE DAY.  
   
OUTLOOK FOR 00Z TUESDAY THROUGH FRIDAY
 
   
MONDAY NIGHT THROUGH THURSDAY
 
MVFR OR LOWER CONDS IN RAIN. BEST  
CHANCES TUESDAY THROUGH WEDNESDAY.    
FRIDAY
 
IMPROVING CONDS. NW WINDS 15-20 KT WITH 20-25 KT GUSTS.  
 

 
   
MARINE
 
 
SCA WILL GRADUALLY COME DOWN FROM WEST TO EAST ACROSS THE WATERS  
TONIGHT...WITH THE EASTERN OCEAN WATERS TAKING THE LONGEST. HIGH  
PRESSURE BUILDS IN FROM THE WEST WITH A DIMINISHING NW FLOW...AND  
SWELLS FROM DISTANT HURRICANE GONZALO CONTINUE TO DIMINISH. HIGH  
PRESSURE WILL THEN PASS OFF THE MID ATLANTIC COAST MON WITH A  
RETURN SW FLOW. CONDITIONS ARE FORECAST TO REMAIN BELOW SCA  
CRITERIA THROUGH MON NIGHT.  
 
SUB-SMALL CRAFT CONDITIONS ARE MOST LIKELY ON ALL WATERS TUESDAY  
THROUGH FRIDAY. WIND GUSTS SHOULD BE AROUND 20 KT FROM WEDNESDAY  
INTO THURSDAY NIGHT...AND COULD POSSIBLY REACH 25 KT MAINLY ON THE  
COASTAL OCEAN WATERS IN THIS TIME FRAME. ALSO...SEAS ON THE COASTAL  
OCEAN WATERS EAST OF MORICHES INLET COULD REACH 5 FT ON  
WEDNESDAY...AND POSSIBLY ON THE REMAINDER OF THE COASTAL OCEAN  
WATERS FROM WEDNESDAY NIGHT INTO THURSDAY NIGHT.  
 
FOR NOW THERE IS TOO MUCH UNCERTAINTY TO FORECAST SMALL CRAFT  
CONDITIONS DURING THE MIDDLE OF THE WEEK..EXCEPT FOR THE SCA LEVEL  
SEAS EAST OF MORICHES INLET ON WEDNESDAY.  
 

 
   
HYDROLOGY
 
 
THERE IS THE POTENTIAL FOR AROUND AN INCH OF RAIN FROM TUESDAY INTO  
THURSDAY. BECAUSE THIS WILL BE SPREAD OVER AROUND 48 HOURS...THERE  
DOES NOT APPEAR TO BE AN SIGNIFICANT HYDROLOGIC IMPACT EXPECTED AT  
THIS TIME.  
 

 
   
OKX WATCHES/WARNINGS/ADVISORIES
 
 
CT...FROST ADVISORY UNTIL 8 AM EDT MONDAY FOR CTZ009>012.  
FREEZE WARNING UNTIL 8 AM EDT MONDAY FOR CTZ005>008.  
NY...FROST ADVISORY UNTIL 8 AM EDT MONDAY FOR NYZ069-070-079>081.  
FREEZE WARNING UNTIL 8 AM EDT MONDAY FOR NYZ067-068.  
NJ...FROST ADVISORY UNTIL 8 AM EDT MONDAY FOR NJZ004-103-105-107.  
FREEZE WARNING UNTIL 8 AM EDT MONDAY FOR NJZ002.  
MARINE...SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ330-340-  
355.  
SMALL CRAFT ADVISORY UNTIL 5 AM EDT MONDAY FOR ANZ350-353.  
 

 
 

 
SYNOPSIS...MALOIT/DW  
NEAR TERM...JM/DW  
SHORT TERM...DW  
LONG TERM...MALOIT  
AVIATION...MET  
MARINE...MALOIT/DW  
HYDROLOGY...MALOIT/DW  
 
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