231  
FXUS61 KOKX 210153  
AFDOKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW YORK NY  
953 PM EDT FRI APR 20 2018  
   
SYNOPSIS
 
 
HIGH PRESSURE BUILDS IN FROM THE WEST THROUGH TONIGHT, THEN  
REMAINS OVER THE REGION INTO MONDAY. A COASTAL LOW WILL LIKELY  
AFFECT THE REGION THE MIDDLE OF NEXT WEEK.  
 

 
   
NEAR TERM /UNTIL 6 AM SATURDAY MORNING/
 
 
FORECAST IS ON TRACK WITH ONLY MINOR CHANGES MADE.  
 
AN UPPER LONGWAVE TROUGH ALONG THE EASTERN CANADIAN COAST AND  
EXTENDING INTO THE NORTHEAST REMAINS THROUGH TONIGHT WITH A  
NORTHWEST CYCLONIC FLOW. MEANWHILE SURFACE LOW PRESSURE ALONG  
THE CANADIAN COAST TRACKS NORTHEAST AS HIGH PRESSURE BUILDS TO  
THE WEST. THE ATMOSPHERE WILL REMAIN DRY AND CLOUD-FREE TONIGHT.  
WINDS WILL BE DIMINISHING, AND LIKELY DECOUPLE LATE TONIGHT.  
THIS WILL ALLOW FOR GOOD RADIATIONAL COOLING WITH CLEAR  
CONDITIONS. INLAND AREAS WILL LIKELY SEE PATCHY TO AREAS OF  
FROST AND INCLUDED IN THE WEATHER FORECAST. HOWEVER, THE SPRING  
FROST/FREEZE PROGRAM HAS NOT BEGUN ACROSS THESE AREAS.  
 

 
   
SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/
 
 
THE UPPER TROUGH REMAINS ACROSS THE NORTHEAST THROUGH SATURDAY  
NIGHT AS THE CENTER OF THE SURFACE HIGH BUILDS INTO THE  
NORTHEAST. THE WEATHER WILL REMAIN QUIET AND CLOUD FREE.  
CYCLONIC FLOW AND WEAK COLD ADVECTION CONTINUE THROUGH SATURDAY  
NIGHT, HOWEVER, THE AIRMASS WILL BE MODIFYING UNDER FULL SUN,  
AND HIGHS SATURDAY WILL BE APPROACHING NORMAL LEVELS. SATURDAY  
NIGHT WILL BE CLOUD-FREE WITH LIGHT WINDS AND AGAIN THERE WILL  
BE IDEAL RADIATIONAL COOL CONDITIONS. SO, EXPECT AREAS AND  
PATCHY FROST INLAND.  
 

 
   
LONG TERM /SUNDAY THROUGH FRIDAY/
 
 
UPPER AIR PATTERN WILL VERY MUCH RESEMBLE EARLY SPRINGTIME  
AS AN UPPER LOW OVER THE MISSISSIPPI VALLEY SLOWLY WORKS EAST  
ON THE HEELS OF A DEPARTING NORTHERN BRANCH TROUGH OVER THE  
NORTHEAST. RIDGING BOTH ALOFT AND AT THE SURFACE BUILDS ACROSS  
THE REGION TO START THE WEEK BUT THEN GIVES WAY TO THE  
AFOREMENTIONED SOUTHERN BRANCH CLOSE LOW. THE SYSTEM WILL LIFT  
NORTHWARD IN RESPONSE TO A NORTHERN BRANCH SHORTWAVE TROUGH  
MOVING INTO THE UPPER MIDWEST AND GREAT LAKES, SENDING SURFACE  
LOW PRESSURE UP THE EASTERN SEABOARD TUESDAY INTO WEDNESDAY.  
 
OVERRUNNING RAINS ARE FORECAST TO DEVELOP ACROSS THE AREA  
TUESDAY NIGHT AND CONTINUE INTO WEDNESDAY NIGHT. THERE ARE  
SOME DIFFERENCES THEREAFTER THOUGH WITH THE GLOBAL MODELS AS  
THE ECWMF IS MORE PROGRESSIVE WITH THIS SYSTEM AND DRIES THINGS  
OUT FOR THE END OF WEEK, WHILE THE GFS AND GGEM CLOSE OFF THE  
NORTHERN BRANCH TROUGH WITH UNSETTLED CONDITIONS LINGERING UNTIL  
A COLD FRONTAL PASSAGE FRIDAY NIGHT. THUS, WILL MAINTAIN A  
LOW CHANCE OF SHOWERS FOR THE END OF THE WEEK. THE POINT TO BE  
MADE HERE THERE IS CLEARLY UNCERTAINTY IN THE GUIDANCE FOR THE  
END OF THE WEEK AS NORTHERN BRANCH SHORTWAVE ENERGY DIVES  
SOUTHEAST ACROSS THE UPPER MIDWEST AND GREAT LAKES REGION.  
HOWEVER, ALL THE GLOBAL MODELS ARE POINTING TO AMPLIFICATION OF  
THE RIDGE OUT WEST AND THE TROUGH REESTABLISHING ITSELF ACROSS  
THE EAST BY NEXT WEEKEND.  
 
AS FOR TEMPERATURES, MUCH OF THE PERIOD WILL FEATURE SEASONABLE  
TEMPERATURES WITH THE EXCEPTION OF WEDNESDAY, WHERE ONSHORE  
FLOW WILL KEEP HIGHS SEVERAL DEGREES BELOW NORMAL.  
 

 
   
AVIATION /02Z SATURDAY THROUGH WEDNESDAY/
 
 
VFR AS HIGH PRESSURE BUILDS FROM THE WEST THROUGH SATURDAY  
MORNING, THEN SETTLES OVER THE REGION SATURDAY AFTERNOON AND  
EVENING.  
 
NW WINDS ABATE THIS EVENING, WITH SPEEDS DECREASING TO AROUND  
10KT. WINDS WILL RANGE AROUND 10 KTS LATE SATURDAY MORNING AND  
AFTERNOON. WIND DIRECTION WILL START OFF NW ON SATURDAY, BEFORE  
BECOMING MORE W IN THE AFTERNOON FOR THE NYC METRO AND COASTAL  
TERMINALS, POSSIBLY EVEN SW AT KJFK/KGON/KBDR/KISP, WITH EXACT  
TIMING UNCERTAIN.  
 
...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: SEA BREEZE SAT AFTERNOON COULD START EARLIER  
AND BECOME MORE SOUTHERLY THAN FORECAST.  
 
KLGA TAF COMMENTS: NO UNSCHEDULED AMD EXPECTED.  
 
KEWR TAF COMMENTS: NO UNSCHEDULED AMD EXPECTED.  
 
KTEB TAF COMMENTS: NO UNSCHEDULED AMD EXPECTED.  
 
KHPN TAF COMMENTS: NO UNSCHEDULED AMD EXPECTED.  
 
KISP TAF COMMENTS: CHANCE THAT SW SEA BREEZE COULD ARRIVE AFTER  
21Z SAT.  
   
OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY
 
   
SATURDAY NIGHT THROUGH TUESDAY
 
VFR.   
TUESDAY NIGHT THROUGH WEDNESDAY
 
SUB VFR CONDITIONS  
INCREASINGLY LIKELY.  
 

 
   
MARINE
 
 
HIGH PRESSURE CONTINUES TO BUILD INTO THE WATERS FROM THE WEST  
WITH THE PRESSURE GRADIENT FORCE GRADUALLY WEAKENING. SEAS ON  
THE OCEAN WATERS HAVE SUBSIDED TO BELOW SCA LEVELS. ALSO, WINDS  
AND GUSTS WERE GENERALLY BELOW SCA LEVELS, ESPECIALLY ACROSS  
THE OPEN OCEAN WATERS. HOWEVER, THROUGH EARLY THIS EVENING  
OCCASIONAL NEARSHORE GUSTS MAY REACH 25 KT. WITH FREQUENT GUSTS  
AND SEAS BELOW SCA LEVELS THE SCA WAS CANCELLED.  
 
HIGH PRESSURE WILL BE ACROSS THE FORECAST WATERS SATURDAY AND  
SATURDAY NIGHT WITH WINDS AND SEAS REMAINING BELOW SCA LEVELS.  
 
TRANQUIL CONDITIONS ARE FORECAST SUNDAY THROUGH TUESDAY AS HIGH  
PRESSURE BUILDS ACROSS THE WATERS. HOWEVER, LOW PRESSURE MOVING UP  
THE EASTERN SEABOARD TUESDAY INTO WEDNESDAY WILL RESULT IN  
INCREASING WINDS AND BUILDING SEAS WITH SCA CONDITIONS LIKELY TO  
RETURN BY WEDNESDAY MORNING.  
 

 
   
HYDROLOGY
 
 
DRY CONDITIONS ARE EXPECTED THROUGH EARLY NEXT WEEK.  
 
A WIDESPREAD RAINFALL IS EXPECTED FOR THE MIDDLE OF NEXT WEEK  
WITH THE POSSIBILITY MODERATE TO HEAVY RAIN. PREDICTABILITY IS  
LOW ON RAINFALL AMOUNTS AND HYDROLOGIC IMPACTS AT THIS TIME.  
 

 
   
EQUIPMENT
 
 
NYC NOAA WEATHER RADIO STATION KWO-35 (162.55 MHZ) REMAINS OFF  
THE AIR.  
 

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

 
 

 
SYNOPSIS...MET/DW  
NEAR TERM...JP/MET  
SHORT TERM...MET  
LONG TERM...DW  
AVIATION...  
MARINE...MET/DW  
HYDROLOGY...MET/DW  
EQUIPMENT...  
 
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