152  
FXUS61 KOKX 151102  
AFDOKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW YORK NY  
702 AM EDT WED AUG 15 2018  
   
SYNOPSIS
 
 
WEAK HIGH PRESSURE WILL BE OVER THE REGION THROUGH THURSDAY.  
A WARM FRONT PASSES FRIDAY, FOLLOWED BY A COLD FRONT FRIDAY NIGHT.  
THE FRONT SETTLES JUST SOUTH OF THE AREA AS WAVES OF LOW PRESSURE  
RIDE ALONG IT THROUGH THE WEEKEND. HIGH PRESSURE BRIEFLY BUILDS  
MONDAY BEFORE ANOTHER FRONTAL SYSTEM APPROACHES FROM THE PLAINS  
STATES TUESDAY.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
AN UPPER RIDGE AND SURFACE HIGH BUILD IN FROM THE WEST TODAY.  
MOSTLY SUNNY, AND WITH A WESTERLY FLOW PLUS 850MB TEMPS AROUND  
17C, HIGHS IN THE UPPER 80S TO LOWER 90S. MAV/MET MOS GUIDANCE  
FOR THIS AFTERNOON'S SURFACE DEWPOINTS HAS TRENDED LOWER SINCE  
YESTERDAY'S GUIDANCE AS EXPECTED. THE WESTERLY FLOW COMBINED  
WITH PROGGED DEWPOINTS THROUGH THE MIXED LAYER WILL ALLOW FOR  
SURFACE DEWPOINTS TO MIX OUT FROM THIS MORNING'S VALUES.  
THINKING IS THAT EVEN IN SPITE OF RELATIVELY WETTER GROUNDS, A  
BLEND OF THE MOS IS STILL NOT MIXING OUT SURFACE DEWPOINTS  
ENOUGH, SO HAVE GONE SLIGHTLY BELOW A BLEND. EVEN WITH THIS  
HOWEVER, THERE'S STILL ENOUGH COVERAGE OF 95+ DEGREE HEAT  
INDICES TO GO WITH A HEAT ADVISORY FOR THE CITY AND THE ADJACENT  
SUBURBS.  
 
THERE IS A MODERATE RISK OF RIP CURRENT DEVELOPMENT AT THE OCEAN  
BEACHES TODAY.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/
 
 
UPPER RIDGE FLATTENS AS ITS AXIS SHIFTS INTO THE REGION LATE  
THURSDAY. WEAK HIGH PRESSURE REMAINS IN PLACE, AND IT SHOULD REMAIN  
RAIN-FREE ACROSS THE ENTIRE AREA THROUGH THURSDAY AFTERNOON.  
 
LOW TEMPERATURES FOR TONIGHT WILL BE ABOVE NORMAL. 850MB  
TEMPERATURES RISE SLIGHTLY, SO EXPECTING THURSDAY'S HIGHS TO BE  
SLIGHTLY WARMER THAN TODAY'S. WINDS THIS TIME WILL BE MORE SW WITH  
SLIGHTLY HIGHER DEWPOINTS THROUGH THE MIXED LAYER. SURFACE DEWPOINTS  
THEREFORE SHOULD BE A LITTLE HIGHER THAN YESTERDAY, MORE SO FOR  
COASTAL AREAS, BUT DRIER GROUNDS COULD HELP DEWPOINTS DROP A LITTLE  
MORE THAN ANTICIPATED ELSEWHERE. IT APPEARS THAT 95+ DEGREE HEAT  
INDICES WILL BE MORE WIDESPREAD, AND A HEAT ADVISORY COULD  
EVENTUALLY BE NEEDED FOR MORE LOCATIONS ACROSS THE TRI-STATE AREA ON  
THURSDAY DEPENDING ON WHETHER OR NOT FRIDAY SEES SIMILAR COVERAGE.  
 
THERE IS A LOW RISK OF RIP CURRENT DEVELOPMENT AT THE OCEAN BEACHES  
ON THURSDAY.  
 

 
   
LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/
 
 
UPPER RIDGE THURSDAY NIGHT WILL GIVE WAY TO LOWERING HEIGHTS AS A  
SHORTWAVE APPROACHES AND SETTLES OVER THE NORTHEAST THIS WEEKEND.  
MODELS REMAIN IN GENERAL AGREEMENT.  
 
THEN RIDGE BUILDS EARLY NEXT WEEK AS UPSTREAM SHORTWAVE, THEN  
LONGWAVE TROUGH EXTENDING FROM CENTRAL CANADA APPROACHES TUESDAY.  
 
AT THE SFC, A WARM FRONT LIFTS TO THE NORTH THURSDAY NIGHT AND  
FRIDAY AS LOW PRESSURE PASSES TO THE NORTH ACROSS NEW ENGLAND BY  
FRIDAY. A PREFRONTAL TROUGH DEVELOPS TO THE LEE OF THE APPALACHIANS,  
AND THE MAIN COLD FRONT APPROACHES FRIDAY NIGHT INTO SATURDAY.  
 
THE FRONT PASSES JUST OFFSHORE AS WAVES OF LOW PRESSURE RIDE ALONG  
IT THROUGH THE WEEKEND. HIGH PRESSURE BUILDS TO THE NORTH DURING  
THIS TIME FRAME. THE FRONT WILL FINALLY DEPART BY MONDAY AS THE  
RIDGE REMAINS IN PLACE. THEN THE NEXT FRONTAL SYSTEM APPROACHES AND  
COULD IMPACT THE AREA AS EARLY AS TUESDAY.  
 
DRY CONDITIONS THURSDAY NIGHT GIVE WAY TO AN INCREASING AMOUNT OF  
CLOUDS, AND SHOWER/THUNDERSTORM CHANCES INCREASE FRIDAY. SOME OF  
THESE SHOWERS COULD PRODUCE HEAVY RAIN AS PW VALUES ARE PROGGED TO  
INCREASE TO OVER TWO INCHES. LOW LEVEL SW FLOW PREVAILS BY THIS TIME  
AHEAD OF THE TROUGH.  
 
THIS WEEKEND LOOKS TO BE UNSETTLED, BUT DO NOT ANTICIPATE A WASHOUT  
BY ANY MEANS AT THIS TIME. MODELS DIFFER IN SHOWER  
DEVELOPMENT/COVERAGE SATURDAY AS THE AREA SITS TO THE NORTH OF THE  
FRONT, AND UPPER TROUGH PASSES. CANNOT RULE OUT A PASSING SHOWER OR  
THUNDERSTORM. A SIMILAR SCENARIO EXISTS FOR SUNDAY, BUT WILL KEEP  
RAIN CHANCES LOW AT THIS TIME THIS WEEKEND.  
 
DRY WEATHER IS FORECAST MONDAY, THEN SHOWER/THUNDERSTORM CHANCES  
INCREASE YET AGAIN BY TUESDAY.  
 
WARM/HOT TEMPS CONTINUE FRIDAY, AND RELATIVELY HIGH HUMIDITY SHOULD  
RESULT IN HEAT INDICES IN THE 90S MOST LOCATIONS. BEHIND THE FRONT,  
TEMPS COOL OFF CLOSER TO NORMAL THIS WEEKEND. SUNDAY LOOKS TO BE THE  
COOLEST DAY THANKS TO NORTHEAST/EAST BREEZES. NEAR NORMAL TEMPS ARE  
ANTICIPATED EARLY NEXT WEEK.  
 

 
   
AVIATION /12Z WEDNESDAY THROUGH SUNDAY/
 
 
WEAK HIGH PRES BUILDS IN TODAY.  
 
MAINLY VFR THRU THE TAF PERIOD. PATCHY MVFR CIGS E OF THE CITY  
ARPTS WILL DISSIPATE BY 13Z.  
 
W WINDS TODAY WITH GUSTS UP TO 20KT. WINDS LIGHTEN TNGT, THEN  
REMAIN GENERALLY AOB 10KT THU.  
 
NY METRO ENHANCED AVIATION WEATHER SUPPORT...  
 
DETAILED INFORMATION, INCLUDING HOURLY TAF WIND COMPONENT FCSTS,  
CAN BE FOUND AT: HTTP:/WWW.WEATHER.GOV/ZNY/N90  
 
KJFK TAF COMMENTS: NO UNSCHEDULED AMENDMENTS ARE EXPECTED.  
 
THE AFTERNOON KJFK HAZE POTENTIAL FORECAST IS GREEN, WHICH IMPLIES  
SLANT RANGE VISIBILITY P6SM OUTSIDE OF CLOUD.  
 
KLGA TAF COMMENTS: NO UNSCHEDULED AMENDMENTS ARE EXPECTED.  
 
THE AFTERNOON KLGA HAZE POTENTIAL FORECAST IS GREEN, WHICH IMPLIES  
SLANT RANGE VISIBILITY P6SM OUTSIDE OF CLOUD.  
 
KEWR TAF COMMENTS: NO UNSCHEDULED AMENDMENTS ARE EXPECTED.  
 
THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN, WHICH IMPLIES  
SLANT RANGE VISIBILITY P6SM OUTSIDE OF CLOUD.  
 
KTEB TAF COMMENTS: NO UNSCHEDULED AMENDMENTS ARE EXPECTED.  
 
KHPN TAF COMMENTS: NO UNSCHEDULED AMENDMENTS ARE EXPECTED.  
 
KISP TAF COMMENTS: NO UNSCHEDULED AMENDMENTS ARE EXPECTED.  
   
OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY
 
   
THURSDAY
 
VFR WITH WINDS BACKING TO THE SW.   
FRIDAY
 
MVFR OR LOWER CONDITIONS POSSIBLE IN LATE DAY/EVENING  
SHOWERS AND TSTMS. S FLOW 15-25 KT.   
SATURDAY AND SUNDAY
 
MVFR OR LOWER AT TIMES. SHWRS AND TSTMS  
POSSIBLE. W FLOW BECOMING N.  
 

 
   
MARINE
 
 
CONDITIONS WILL BE JUST BELOW ADVISORY CRITERIA ACROSS THE OCEAN  
TODAY, WITH THE REST OF THE WATERS ALSO BELOW SCA CRITERIA. WINDS  
BECOME LIGHTER TONIGHT AND THURSDAY, ALLOWING FOR WAVES/SEAS TO  
DIMINISH AS WELL.  
 
SOUTHERLY FLOW THURSDAY NIGHT WILL INCREASE FRIDAY AHEAD OF AN  
APPROACHING COLD FRONT. GENERALLY EXPECT WINDS FOR ALL WATERS AND  
OCEAN SEAS TO REMAIN BELOW SCA THRESHOLDS.  
 
WINDS WILL SHIFT TO THE WEST FRIDAY NIGHT, THEN EVENTUALLY VEER TO  
THE NORTH/NORTHEAST THIS WEEKEND AS A COLD FRONT PASSES. SPEEDS  
INCREASE BY SUNDAY AS WAVES OF LOW PRESSURE RIDE ALONG THE STALLED  
FRONTAL BOUNDARY TO THE SOUTH AND EAST. HIGH PRESSURE BUILDS TO THE  
NORTH. OCEAN SEAS MAY BUILD CLOSE TO 5 FT SUNDAY, OTHERWISE WINDS  
AND SEAS REMAIN BELOW SCA THRESHOLDS ACROSS THE REMAINDER OF THE  
WATERS.  
 

 
   
HYDROLOGY
 
 
SHOWERS AND THUNDERSTORMS AHEAD OF A FRONTAL BOUNDARY FRIDAY WILL  
LIKELY PRODUCE HEAVY RAIN IN SPOTS, MAINLY DURING THE AFTERNOON AND  
EVENING HOURS. DEEP LAYER SW FLOW NEARLY PARALLEL TO THE APPROACHING  
FRONTAL BOUNDARY WILL INCREASE MOISTURE OVER THE REGION WITH PW  
EXPECTED TO REACH OVER 2 INCHES. AS A RESULT, THERE IS POTENTIAL FOR  
HEAVY RAIN AND THUS FLOODING WITH INDIVIDUAL CELLS AND ALSO TRAINING  
OF CELLS, MAINLY FROM THE NYC METRO AREA NORTH/WEST.  
 

 
   
EQUIPMENT
 
 
NYC NOAA WEATHER RADIO STATION KWO-35 (162.55 MHZ) REMAINS OFF  
THE AIR FOR AN EXTENDED PERIOD OF TIME.  
 

 
   
OKX WATCHES/WARNINGS/ADVISORIES
 
 
CT...NONE.  
NY...HEAT ADVISORY FROM NOON TODAY TO 6 PM EDT THURSDAY FOR  
NYZ071>075-176>179.  
NJ...HEAT ADVISORY FROM NOON TODAY TO 6 PM EDT THURSDAY FOR NJZ006-  
104-106>108.  
MARINE...NONE.  
 

 
 

 
SYNOPSIS...JC/PW  
NEAR TERM...JC/PW  
SHORT TERM...JC  
LONG TERM...PW  
AVIATION...JMC  
MARINE...JC/PW  
HYDROLOGY...JC/PW  
EQUIPMENT...  
 
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