489  
FXUS61 KOKX 310822  
AFDOKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW YORK NY  
422 AM EDT FRI JUL 31 2015  
   
SYNOPSIS
 
 
A COLD FRONT MOVES FARTHER SOUTHEAST OF LONG ISLAND THIS  
MORNING...FOLLOWED BY WEAK HIGH PRESSURE MOVING ACROSS THE AREA  
THROUGH TONIGHT. THE HIGH PRESSURE AREA DEPARTS EARLY SATURDAY. A  
SERIES OF WEAK FRONTAL BOUNDARIES WILL THEN IMPACT THE AREA OVER  
THE REST OF THE WEEKEND AND INTO THE NEW WEEK. IN BETWEEN....WEAK  
HIGH PRESSURE WILL PREVAIL ACROSS THE AREA.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
DESPITE A NEGATIVE HEIGHT TENDENCY IN THE MID TO UPPER  
LEVELS...WEAK HIGH PRESSURE BUILDS IN AT THE SURFACE FROM THE  
SOUTHWEST. THE SURFACE WESTERLY FLOW BEHIND A COLD FRONT WILL  
PROMOTE DRIER CONDITIONS TODAY. EXPECTING A QUICK DIURNAL WARMING  
AS ANY PATCHY FOG DISSIPATES LATER ON THIS MORNING.  
 
THE DEWPOINTS WILL BE REMARKABLY LOWER...IN THE MID 50S TO LOWER  
60S FOR MOST LOCATIONS...MAKING FOR LESS HUMID CONDITIONS. THE  
TEMPERATURES HOWEVER...WILL BE A FEW DEGREES WARMER THAN THE  
PREVIOUS DAY...WITH MANY LOCATIONS IN THE UPPER 80S TO AROUND 90.  
THE SUBSIDENCE FROM THE WEAK HIGH WILL ALLOW FOR LESS CLOUDS.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM SATURDAY/
 
 
FOR TONIGHT...HIGH PRESSURE CONTINUES TO BUILD IN FOR THE FIRST  
HALF...THEN SLIGHTLY SHIFTS AWAY OVERNIGHT INTO SATURDAY. THE  
CLOUDS WILL BE MINIMAL TO START BUT WILL INCREASE OVERNIGHT WITH  
THE DECREASING SUBSIDENCE. THIS FACTOR WILL LEAD TO RELATIVE  
WARMER LOW TEMPERATURES AT NIGHT IN ADDITION TO THE RETURN  
SOUTHERLY FLOW. LOWS FORECAST WILL BE RANGING FROM THE LOWER 60S  
TO LOWER 70S FOR THE MAJORITY OF THE FORECAST REGION WITH THE  
WARMER VALUES NEAR NYC AND ACROSS LONG ISLAND AS WELL AS ACROSS  
PARTS OF THE CONNECTICUT COAST.  
 
FOR SATURDAY...A COLD FRONT APPROACHES FROM THE WEST. DAYTIME  
TROUGH DEVELOPMENT IS INDICATED IN THE MODELS. A STRONGER  
SOUTHERLY FLOW WILL ALLOW FOR MODERATION OF THE AIRMASS WITH  
SLIGHTLY COOLER READINGS WITH THE MARITIME INFLUENCE. STILL IT  
WILL BE VERY WARM WITH HIGHS IN THE MID TO UPPER 80S FOR MOST  
LOCATIONS AND LOWER 90S FOR PARTS OF NYC AND URBAN NEW JERSEY. IN  
ADDITION...THE HUMIDITY WILL BE BACK ON THE RISE WITH THE ONSHORE  
FLOW AS DEWPOINTS INCREASE TO THE UPPER 50S TO MID 60S. SOME  
MODELS ARE INDICATING SOME CONVECTION FOR THE AFTERNOON HOURS BUT  
WITHOUT MUCH COHERENCY BETWEEN MODEL SOLUTIONS...WENT WITH SLIGHT  
CHANCE FOR TIME BEING.  
 

 
   
LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/
 
 
A BROAD UPPER TROF FROM CENTRAL CANADA SE INTO THE NORTHEAST QUARTER  
OF THE NATION WILL BE IN CONTROL OF THE WEATHER DURING THIS TIME  
PERIOD.  
 
FOR THE MOST PART...MAINLY TRANQUIL CONDS ON TAP FOR THE REGION  
DURING THIS PERIOD. A SERIES OF WEAK COLD FRONTS WILL MOVE ACROSS  
THE REGION STARTING SATURDAY NIGHT AND CONTINUING THROUGH THE MIDDLE  
OF NEXT WEEK. FOR NOW...EXPECTING WIDELY SCT SHOWERS/TSTMS SATURDAY  
EVENING...THEN DRY CONDS PREVAIL UNTIL THE NEXT COLD FRONT MONDAY  
NIGHT INTO TUESDAY. NOT EXPECTING MUCH IN THE WAY OF PRECIP WITH  
EACH FRONT...AND IN BETWEEN...WEAK HIGH PRES WILL RULE. A STRONGER  
COLD FRONT MOVES THOUGH ON WED AND LOOKS TO STALL JUST SOUTH OF THE  
REGION WITH A WAVE OF LOW PRESSURE TRACKING ACROSS THE MID ATLANTIC  
STATES. THERE ARE SOME TIMING ISSUES AMONGST THE GLOBAL MODELS.  
FORECAST AREA LOOKS TO BE ON THE NORTHERN PERIPHERY OF THE SYSTEM.  
FOR NOW...WILL JUST HAVE A LOW CHANCE FOR SHOWERS.  
 
AT THE ONSET...TEMPS DURING THE PERIOD WILL BE NEAR TO SLIGHTLY  
ABOVE NORMAL WITH HIGHS GENERALLY IN THE 80S TO AROUND 90. HUMIDITY  
LEVELS WILL BE LOW SUNDAY...AND THEN WILL START TO CREEP UP EARLY IN  
THE WEEK BEFORE ANOTHER COLD FRONT MOVES THROUGH MON NIGHT INTO TUE  
WITH ANOTHER SHOT OF DRIER AIR FOR THE MID WEEK. TEMPS RETURN TO  
NEARLY SEASONABLE LEVELS FOR WED AND THU.  
 

 
   
AVIATION /08Z FRIDAY THROUGH TUESDAY/
 
 
COLD FRONT WILL CONTINUE TO TRACK ACROSS THE AREA...AND SHOULD BE  
E OF ALL TERMINALS BETWEEN 10-12Z. PATCHY MVFR TO LOCALLY IFR  
CONDS POSSIBLE THROUGH THIS TIME...OUTSIDE OF THE METRO WITH  
MINIMAL DEWPOINT DEPRESSIONS. VFR THEREAFTER. WINDS WILL REMAIN  
LIGHT (LESS THAN 10KT) UNTIL MID MORNING OR SO. A SFC TROUGH  
DEVELOPS LATE MORNING/EARLY AFTN RESULTING IN BACKING OF WINDS TO  
THE W. GUSTS UP TO 20KT IN THE AFTN...MAINLY COASTAL TERMINALS.  
 
SEABREEZE DEVELOPMENT IS DIFFICULT TO SAY ATTM WITH A DECENT  
SYNOPTIC FLOW. GUIDANCE WAS TOO WEAK WITH WINDS ALOFT YESTERDAY  
AND IF THAT IS THE CASE AGAIN TODAY...IT WILL BE TOUGH TO  
DEVELOP. HAVE INCLUDED IT AT KBDR AND HAVE HINTED AT THE  
POSSIBILITY AT KJFK/KGON FOR NOW.  
   
..NY METRO ENHANCED AVIATION WEATHER SUPPORT
 
 
DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS  
CAN BE FOUND AT:  
HTTP://WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE)  
 
KJFK FCSTER COMMENTS: WINDS RIGHT OF 310 MAGNETIC THROUGH THIS  
MORNING. TIMING OF WINDS BACKING TO THE LEFT OF 310 COULD BE 1-2  
HOURS LATER THAN FORECAST. SEABREEZE POSSIBLE AFT 18Z.  
 
KLGA FCSTER COMMENTS: WINDS RIGHT OF 310 MAGNETIC THROUGH THIS  
MORNING. TIMING OF WINDS BACKING TO THE LEFT OF 310 COULD BE 1-2  
HOURS LATER THAN FORECAST. SEABREEZE POSSIBLE LATE (AFT 22Z).  
 
KEWR FCSTER COMMENTS: WINDS RIGHT OF 310 MAGNETIC THROUGH THIS  
MORNING. TIMING OF WINDS BACKING TO THE LEFT OF 310 COULD BE 1-2  
HOURS LATER THAN FORECAST.  
 
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH  
IMPLIES  
SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD.  
 
KTEB FCSTER COMMENTS: TIMING OF WINDS BACKING TO THE W COULD BE  
1-2 HOURS LATER THAN FORECAST.  
 
KHPN FCSTER COMMENTS: TIMING OF WINDS BACKING TO THE W COULD BE  
1-2 HOURS LATER THAN FORECAST.  
 
KISP FCSTER COMMENTS: TIMING OF WINDS BACKING TO THE W COULD BE  
1-2 HOURS LATER THAN FORECAST. SEABREEZE POSSIBLE AFT 20Z.  
   
OUTLOOK FOR 06Z SAT THROUGH TUE
 
   
FRI NIGHT-SUN
 
VFR.   
MON
 
INCREASING S FLOW WITH A CHC OF TSTMS.   
TUE
 
CHC TSTMS. WINDS SHIFTING TO THE W.  
 

 
   
MARINE
 
 
A WEAK PRESSURE GRADIENT ACROSS THE WATERS WILL KEEP CONDITIONS  
BELOW SCA THROUGH TONIGHT. ON SATURDAY...THE SOUTHERLY FLOW WILL  
ALLOW FOR AN INCREASE IN WINDS AND SEAS AS HIGH PRESSURE MOVES  
AWAY FROM THE REGION. SCA WILL BE POSSIBLE BUT CONFIDENCE IS NOT  
HIGH ENOUGH IN THIS TIMEFRAME TO WARRANT ANY ISSUANCE OF SCA AT  
THIS TIME.  
 
THEREAFTER...A SERIES OF FRONTAL BOUNDARIES WILL IMPACT THE  
WATERS OVER THE REST OF THE WEEKEND AND INTO THE NEW WEEK. OCEAN  
SEAS MAY BUILD TO 5 FT DURING THIS TIME DUE TO A PREVAILING S/SW  
FLOW.  
 

 
   
HYDROLOGY
 
 
NO SIGNIFICANT WIDESPREAD RAIN EXPECTED.  
 

 
   
OKX WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
NY...NONE.  
NJ...NONE.  
MARINE...NONE.  
 

 
 

 
SYNOPSIS...JM  
NEAR TERM...JM  
SHORT TERM...JM  
LONG TERM...DW  
AVIATION...24  
MARINE...JM/DW  
HYDROLOGY...JM/DW  
 
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