090  
FXUS61 KOKX 241653  
AFDOKX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE NEW YORK NY  
1253 PM EDT SUN JUN 24 2018  
   
SYNOPSIS
 
 
A COLD FRONT CROSSES THE AREA THIS AFTERNOON AND EVENING  
FOLLOWED BY HIGH PRESSURE BUILDING IN THROUGH MID-WEEK. A WARM  
FRONT THEN APPROACHES FROM THE SOUTHWEST WEDNESDAY, THEN SLOWLY  
LIFTS TO THE NORTHEAST INTO THURSDAY. A WEAK COLD FRONT WILL  
THEN APPROACH ON THURSDAY AND POSSIBLY DISSIPATE OVER THE REGION  
FRIDAY INTO SATURDAY.  
 

 
   
NEAR TERM /UNTIL 6 PM THIS EVENING/
 
 
MINOR CHANGES WERE MADE WITH THIS UPDATE TO REFLECT THE LATEST  
TRENDS IN OBSERVATIONS AND GUIDANCE. THE FORECAST APPEARS ON  
TRACK.  
 
A 700-500 HPA SHORTWAVE TROUGH APPROACHES LATE IN THE DAY. THIS  
FEATURE WILL INTERACT WITH AN ATMOSPHERE THAT SHOULD DESTABILIZE  
FAIRLY RAPIDLY THIS AFTERNOON, ESPECIALLY TO THE N/W OF NYC.  
CAPE IS PROGGED TO REACH 1000-1500 J/KG BY LATE AFTERNOON OVER  
NE NJ/LOWER HUDSON VALLEY INTERIOR SW CT, SO SHOULD HAVE  
SUFFICIENT DYNAMICS AND THERMODYNAMICS TO PRODUCE MAINLY  
SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON. IN ADDITION  
WITH 40-45 KT OF BULK 0-6KM SHEAR PROGGED OVER THIS REGION BY  
LATE AFTERNOON, PLUS THE REGION BEING PROGGED IN THE LEFT FRONT  
QUADRANT OF AN 85 KT 300 HPA JET STREAK, COULD SEE SOME STRONG  
TO POSSIBLY SEVERE THUNDERSTORMS AS WELL.  
 
THE QUESTION THEN BECOMES FOR AREAS OUTSIDE OF THE  
LOWER HUDSON VALLEY/NE NJ/SW CT IS HOW WELL DO THE STORMS HOLD  
TOGETHER AS THEY HEAD EAST INTO AREAS UNDER A MARINE INFLUENCE.  
THIS WILL DETERMINE IMPACTS ELSEWHERE. STORMS MOVING INTO NYC OR  
COASTAL CT BY 21-22Z HAVE A GREATER LIKELIHOOD TO BE STRONG OR  
SEVERE THAN THOSE MOVING IN AROUND 0Z OR LATER.  
 
BASED ON ABOVE THINKING, HAVE UPDATED THE HWO TO REFLECT A LOW  
CHANCE FOR SEVERE WEATHER OVER THE LOWER HUDSON VALLEY/NE  
NJ/MOST OF SW CT. ALSO ADDED MENTION OF GUSTY WINDS IN THIS AREA  
AS WELL.  
 
A MORE WIDESPREAD PROBLEM,AS PRECIPITABLE WATERS INCREASE TO  
AROUND 1/75" IS THE POTENTIAL FOR LOCALLY HEAVY RAINFALL. HAVE  
ADDED A MENTION OF LOCALLY HEAVY RAIN IN THE FORECAST WHEREVER  
THERE WERE CHANCE POPS OR GREATER INTO TONIGHT (SO THIS COVERS  
MOST OF THE CWA EXCEPT FOR PORTIONS OF LONG ISLAND). REFER TO  
THE HYDROLOGY SECTION OF THE AFD FOR DETAILS ON AMOUNTS AND ANY  
POTENTIAL IMPACTS.  
 
STILL APPEAR ON TRACK FOR HIGHS MAINLY FROM AROUND 80 TO THE MID  
80S, EXCEPT MAINLY MID-UPPER 70S NEAR THE IMMEDIATE COAST.  
 
THERE IS A HIGH RIP CURRENT RISK AT THE EASTERN SUFFOLK COUNTY  
BEACHES, AND A MODERATE RIP CURRENT RISK ELSEWHERE.  
 

 
   
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM MONDAY/
 
 
A COLD FRONT PASSES ACROSS THE AREA FROM WEST TO EAST EARLY TONIGHT.  
WEAKENING SHOWERS AND THUNDERSTORMS WILL ACCOMPANY THIS FRONT  
AND H5 SHORTWAVE. ALONG THE COAST, PATCHY FOG IS POSSIBLE IN  
THE EVENING AHEAD OF THE FRONT, BUT SHOULD SCOUR OUT OVERNIGHT  
AS DRIER AIR FILTERS IN BEHIND THE FRONT.  
 
LOWS TONIGHT WILL RANGE FROM THE LOWER 60S TO THE UPPER 60S PER MOS  
BLEND.  
 
ON MONDAY, SUNSHINE RETURNS, WITH PERHAPS A FEW MORE CLOUDS ACROSS  
EASTERN LOCATIONS (SE CT AND EASTERN LI). A FEW SHOWERS ARE  
POSSIBLE OVER THESE EASTERN LOCATIONS, BUT THE BULK OF THE  
SHOWER ACTIVITY SHOULD PASS FROM NW TO SE OVER EASTERN NEW  
ENGLAND. THIS ACTIVITY WILL BE ASSOCIATED WITH CYCLONIC FLOW AS  
TROUGH AXIS PUSHES EAST.  
 
TEMPERATURES WILL RISE TO THE UPPER 70S TO LOWER 80S.  
 

 
   
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/
 
 
HIGH PRESSURE BUILDS MONDAY NIGHT, AND NW WINDS WILL DIMINISH. WITH  
CLEAR SKIES AND LIGHTER WINDS, SOME RADIATIONAL COOLING WILL TAKE  
PLACE ACROSS THE USUAL LOCATIONS.  
 
THE HIGH PRESSURE CENTER MOVES THROUGH ON TUESDAY WITH SUNNY  
CONDITIONS AND HIGHS SLIGHTLY COOLER, BUT STILL CLOSE TO NORMAL.  
 
THE HIGH WILL BE TO OUR EAST ON WEDNESDAY, AND A RETURN SW FLOW  
WILL BRING WARMER AND MORE HUMID CONDITIONS. IT APPEARS THE  
DAYTIME HOURS FOR MOST AREAS WILL BE DRY AS SHOWERS AHEAD OF AN  
APPROACHING WARM FRONT REMAIN TO THE WEST. THE WARM FRONT MOVES  
THROUGH, THEN A COLD FRONT SLOWLY APPROACHES THURSDAY INTO FRIDAY. A  
SURFACE TROUGH LIKELY FORMS OVER THE AREA AHEAD OF THE COLD FRONT.  
IT'S BEGINNING TO LOOK MORE LIKELY THAT THE FRONT NEVER MAKES IT  
THROUGH THE ENTIRE REGION AND INSTEAD DISSIPATES NEARBY SOMETIME  
FRIDAY INTO SATURDAY. WILL MAINTAIN SLIGHT CHANCE TO CHANCE POPS  
WEDNESDAY NIGHT THROUGH FRIDAY, THEN GO WITH A DRY FORECAST  
THEREAFTER.  
 
RISING TEMPERATURES ALOFT WILL ALLOW FOR HIGHS AROUND 90 IN THE CITY  
AND SOME INLAND AREAS THURSDAY. 90S THEN BECOME MORE WIDESPREAD  
ACROSS THE TRI-STATE AREA FOR FRIDAY AND SATURDAY. A SOUTH TO  
SOUTHWEST FLOW ALONG WITH SUFFICIENTLY HIGH DEWPOINTS THROUGH THE  
TOP OF THE MIXED LAYER WOULD LIMIT THE MAGNITUDE OF SURFACE  
DEWPOINTS MIXING-OUT EACH AFTERNOON. HEAT ADVISORY CRITERIA COULD  
THEREFORE BE MET IN THIS PERIOD, PARTICULARLY FRIDAY AND  
SATURDAY.  
 

 
   
AVIATION /18Z SUNDAY THROUGH FRIDAY/
 
 
A WARM FRONT WILL SLOWLY MOVE THROUGH THE TERMINALS THIS MORNING,  
FOLLOWED BY A COLD FRONT THIS EVENING.  
 
GRADUAL IMPROVEMENT OCCURRING MOSTLY AS ANTICIPATED, EXCEPT OUT  
EAST AT KISP/KGON WHERE VFR NOT EXPECT UNTIL AFTERNOON.  
 
SCATTERED SHOWERS/TSTMS SHOULD ACCOMPANY THE COLD FRONTAL  
PASSAGE LATE THIS AFTERNOON INTO EARLY THIS EVENING. MOST LIKELY  
TIME FRAME APPEARS TO BE 20Z-23Z KSWF, 21Z-01Z KHPN AND MOST OF  
THE NYC METROS, 22Z-02Z KJFK/KBDR. CONFIDENCE LEVEL HAS  
INCREASED ENOUGH TO MENTION VICINITY IMPACT AND CB, BUT NOT  
ENOUGH TO GET SPECIFIC IN TERMS OF FLIGHT CAT REDUCTIONS OR WIND  
GUSTS. REASONABLE WORST CASE DIRECT IMPACT WOULD BE BRIEF IFR  
VSBY AND W-NW WINDS G35-40KT.  
 
SW TO S WINDS WILL STRENGTHEN THROUGH THE AFTERNOON, THEN  
BECOME NW FOLLOWING THE COLD FRONTAL PASSAGE TONIGHT. GUSTS WILL  
BE POSSIBLE BY MONDAY MORNING, WITH FLOW GRADUALLY DECREASING  
THROUGH THE DAY.  
   
OUTLOOK FOR 12Z MONDAY THROUGH THURSDAY
 
   
MONDAY-WEDNESDAY
 
VFR. NW-N WINDS G15-25KT MONDAY-MONDAY  
NIGHT. S-SW WINDS G20-25KT POSSIBLE WEDNESDAY.   
WEDNESDAY NIGHT-THURSDAY
 
MVFR OR LOWER PROBABLE. SHOWERS ARE  
ALSO PROBABLE AND THERE IS A CHANCE OF THUNDERSTORMS AS WELL. SW  
WINDS G15-25KT POSSIBLE.  
 

 
   
MARINE
 
 
MINOR CHANGES WERE MADE WITH THIS UPDATE TO REFLECT THE LATEST  
TRENDS IN OBSERVATIONS AND GUIDANCE. THE FORECAST APPEARS ON  
TRACK.  
 
SUB-SMALL CRAFT ADVISORY (SCA) CONDITIONS ARE EXPECTED ON THE  
WATERS THIS AFTERNOON. ISOLATED GUSTS TO NEAR SCA-LEVELS ARE  
POSSIBLE TONIGHT (OUTSIDE OF ANY THUNDERSTORMS).  
 
CONDITIONS ARE THEN EXPECTED TO REMAIN TRANQUIL MONDAY THROUGH  
TUESDAY WITH A RELAXED PRESSURE GRADIENT DEVELOPING OVER THE  
WATERS. THEREAFTER, THE PRESSURE GRADIENT TIGHTENS RESULTING IN  
A STRENGTHENING S-SW FLOW AND SCA-LEVEL GUSTS POSSIBLE ON ALL  
WATERS WEDNESDAY AFTERNOON THROUGH THURSDAY EVENING. OCEAN SEAS  
WILL INCREASE TO SCA- LEVELS IN RESPONSE TO THE STRENGTHENING  
AND PROLONGED SOUTH-SOUTHWEST FLOW.  
 

 
   
HYDROLOGY
 
 
THERE COULD BE A FEW LOCALLY HEAVY DOWNPOURS THIS AFTERNOON AND  
EVENING. AS A RESULT, THERE IS A LOW END POSSIBILITY FOR MINOR  
FLOODING OF URBAN AND KNOWN POOR DRAINAGE AREAS THAT DO  
EXPERIENCE LOCALLY HEAVY RAINFALL. THE THREAT WILL ALSO BE  
SOMEWHAT DEPENDENT ON STORM MOTION, WHICH AT THIS TIME APPEARS  
SHOULD BE FAST ENOUGH TO HELP MITIGATE ANY POTENTIAL FLOOD  
THREAT. AREAL AVERAGE RAINFALL TOTALS WILL BE AROUND 1/2 INCH OR  
LESS, BUT STRONGER, SLOWER MOVING CONVECTION, COULD PRODUCE  
LOCALLY UP TO AROUND AN INCH.  
 
NO HYDROLOGIC IMPACTS ARE EXPECTED FROM MONDAY THROUGH THE REST  
OF THE FORECAST PERIOD.  
 

 
   
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...HIGH RIP CURRENT RISK UNTIL 9 PM EDT THIS EVENING FOR NYZ081.  
NJ...NONE.  
MARINE...NONE.  
 

 
 

 
 
SYNOPSIS...PW  
NEAR TERM...MALOIT/PW  
SHORT TERM...PW  
LONG TERM...JC/PW  
AVIATION...GOODMAN/MD  
MARINE...MALOIT/MD  
HYDROLOGY...PW  
EQUIPMENT...  
 
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