FXUS61 KOKX 201142 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 742 AM EDT MON MAY 20 2013 .SYNOPSIS... A WARM FRONT LIFTS TO THE NORTH TODAY AND WILL SINK SOUTH CLOSER TO THE AREA ON TUESDAY. A COLD FRONT IN THE VICINITY OF THE AREA TUESDAY NIGHT WILL LIFT BACK AS A WARM FRONT ON WEDNESDAY. A WARM AND HUMID AIRMASS WILL THEN REMAIN OVER THE REGION UNTIL A COLD FRONT MOVES THROUGH THURSDAY NIGHT OR FRIDAY. HIGH PRESSURE RETURNS FOR THE WEEKEND. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... VSBYS HAVE DROPPED TO 1/4 SM OR LESS IN MANY LOCATIONS ON LONG ISLAND...COASTAL CONNECTICUT AND SOUTHERN WESTCHESTER THIS MORNING...SO HAVE ISSUED A DENSE FOG ADVSY FOR THESE AREAS THROUGH 10 AM. ORIGINALLY THOUGHT IT WOULD TAKE A BIT FOR VSBYS TO IMPROVE WITH LIGHT WINDS AT THE SFC...BUT ALREADY SEEING SOME IMPROVEMENT SO THIS MAY BE CANCELLED EARLY. MESOSCALE MODELS ALSO INDICATING DRY WEATHER THIS MORNING AND NOT SEEING ANYTHING IN WATER VAPOR IMAGERY TO TRIGGER ANY SHOWER ACTIVITY...SO HAVE REMOVED POPS UNTIL THIS AFTN. REST OF FORECAST IS ON TRACK. LOW PRESSURE RIDES ALONG A FRONT WELL TO THE NORTH TODAY. WEAK FRONTAL BOUNDARY TO THE SOUTH SHOULD WEAKEN AND DISSIPATE THIS MORNING. DENSE FOG DEVELOPED ALONG AND NORTH OF A FRONTAL BOUNDARY JUST SOUTH OF THE LOCAL AREA. LOW CLOUDS AND FOG WILL SLOWLY BURN OFF AS THE MORNING PROGRESSES. SOME BREAKS OF SUN ARE POSSIBLE THIS AFTERNOON. HOW MUCH CLEARING OCCURS WILL DETERMINE THE AMOUNT OF DAYTIME HEATING/INSTABILITY...WHICH WILL AID IN TSTM DEVELOPMENT THIS AFTERNOON AND EVENING...HOWEVER...THINKING COVERAGE WILL BE ISOLD TO WDLY SCT AT BEST. WITH PW NEAR 1.5...ANY SHOWER/TSTM COULD PRODUCE LOCALLY HEAVY RAIN. WILL MAINTAIN CHANCE POPS. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... FRONTAL BOUNDARY REMAINS JUST TO THE NORTH AS RIDGE PREVAILS ACROSS THE NORTHEAST AHEAD OF UPSTREAM TROUGH. SOUTHWEST LOW LEVEL FLOW WILL LIGHTEN THIS EVENING...AND AMPLE MOISTURE COULD LEAD TO THE DEVELOPMENT OF FOG ONCE AGAIN. ANY LINGERING DIURNAL SHOWERS/TSTMS WILL DIMINISH IN COVERAGE...AND MOST OF THE NIGHT SHOULD BE DRY. WITH AREA IN THE WARM SECTOR...TEMPERATURES WILL REMAIN QUITE MILD...50S TO AROUND 60. ON TUESDAY...TEMPS WARM THROUGH THE 70S...TO AROUND 80 AWAY FROM THE WATER...WITH 70S ELSEWHERE. ANY MORNING FOG WILL BURN OFF TO PARTLY SUNNY SKIES. AFTERNOON SHOWERS OR THUNDERSTORMS ARE POSSIBLE ONCE AGAIN. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... MEDIUM RANGE MODELS/ENSEMBLES ARE IN DECENT GENERAL AGREEMENT WITH THE REGION LYING ON THE NORTHERN PERIPHERY OF EAST COAST RIDGING DURING THE MIDWEEK...WITH PHASING EASTERN CANADIAN AND CENTRAL US TROUGHS...EVENTUALLY TRANSLATING A DEEP TROUGH TO THE EAST COAST FOR THE END OF THE WEEK/WEEKEND. FOR TUESDAY THROUGH THURSDAY...MODELS CONTINUE TO DIFFER IN LOCATION OF A FRONTAL BOUNDARY. THE PREDICTABILITY ISSUES ARE BASED ON SUBTLE DIFFERENCES IN INTERACTION OF THE UPPER ENERGIES AND RELATIONSHIP WITH EAST COAST RIDGING. THE LOCATION OF UPPER CONFLUENCE WILL DETERMINE HOW STRONGLY CANADIAN HIGH PRESSURE BUILDS SE INTO NEW ENGLAND...AND THE TIMING AND MOVEMENT OF A BACK DOOR COLD FRONT. LATEST GUIDANCE DOES NOT BRING THE BACKDOOR COLD FRONT THROUGH THE CWA TUESDAY NIGHT...BUT ITS STILL QUESTIONABLE WHETHER IT SINKS INTO THE AREA OR REMAINS JUST N. HAVE TRENDED IN THIS DIRECTION AND BROUGHT IT ABOUT HALFWAY THROUGH...BUT TEMPS TUE NIGHT WILL BE AFFECTED BY THIS. THE BOUNDARY THEN LIFTS BACK NORTH AS A WARM FRONT ON WEDNESDAY. TO THE SOUTH OF THE FRONT...AN UNSEASONABLY WARM AND MOIST AIR MASS WILL BE IN PLACE. DEPENDING ON THE TIMING AND LOCATION OF THE FRONTAL BOUNDARY...SHORTWAVES AT THE SOUTHERN EDGE OF THE WESTERLIES...FAVORABLE INSTABILITY AND WIND FIELDS PRESENT THE POTENTIAL FOR CONVECTIVE COMPLEXES TO DEVELOP AND PROPAGATE ALONG THIS BOUNDARY. ANY MCS WOULD BRING THE THREAT FOR FLASH FLOODING AND SEVERE WEATHER. MODELS HAVE COME BETTER INTO LINE WITH THE PHASING OF THE MIDWEST UPPER TROUGH AND EASTERN CANADIAN UPPER TROUGH AT THE END OF THE WEEK. COLD FRONT LOOKS TO TRACK THROUGH THE AREA THU NIGHT. A PRE-FRONTAL TROUGH IN THE WARM...MOIST AIRMASS PRECEDING THE FRONT ON THU...WILL BE THE TRIGGER FOR SCT SHOWERS AND TSTMS DURING THE AFTN AND EVE HOURS. THERE IS THE POTENTIAL FOR SOME STORMS TO BE STRONG TO SEVERE BASED ON LATEST PROFILES. LINGERING SHOWERS ARE POSSIBLE ON FRI WITH THE UPPER TROUGH MOVING THROUGH. MODEL GUIDANCE IS SIGNALING A DRIER AND SLIGHTLY BELOW SEASONABLE WEEKEND...WITH EAST COAST MEAN TROUGHING AND CANADIAN HIGH PRESSURE BUILDS INTO THE REGION. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... LOW PRESSURE WILL RIDE ALONG A FRONTAL BOUNDARY WELL TO THE NORTH OF THE AREA TODAY. MORNING FOG AND STRATUS WILL IMPROVE AS THE MORNING PROGRESSES. A FEW SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE IN THE AFTERNOON. HOWEVER TOO ISOLATED TO MENTION IN TERMINAL FORECASTS. VARIABLE WINDS EARLY ON WILL BECOME SOUTHWESTERLY. SEA BREEZE INFLUENCE IS LIKELY. MAINLY VFR THIS EVENING AS ANY SHOWERS OR THUNDERSTORMS WEAKEN. FOG AND STRATUS SHOULD REDEVELOP BY MIDNIGHT. ...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) KEWR FCSTER COMMENTS: AMENDMENTS LIKELY FOR TIMING OF FOG AND STRATUS IMPROVEMENT. WEST WINDS SHOULD TURN TOWARD THE SOUTHWEST THIS MORNING. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KJFK FCSTER COMMENTS: AMENDMENTS LIKELY FOR TIMING OF FOG AND STRATUS IMPROVEMENT. SEA BREEZE POSSIBLE THIS AFTERNOON. KLGA FCSTER COMMENTS: AMENDMENTS LIKELY FOR TIMING OF FOG AND STRATUS IMPROVEMENT. POSSIBLE LATE DAY SEABREEZE. KTEB FCSTER COMMENTS: AMENDMENTS LIKELY FOR TIMING OF FOG AND STRATUS IMPROVEMENT. KHPN FCSTER COMMENTS: AMENDMENTS LIKELY FOR TIMING OF FOG AND STRATUS IMPROVEMENT. KISP FCSTER COMMENTS: AMENDMENTS LIKELY FOR TIMING OF FOG AND STRATUS IMPROVEMENT. .OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY... .TUESDAY-FRIDAY...DURING THE DAY...A CHANCE OF MVFR OF LOWER CONDITIONS IN SHOWERS/TSTMS. AT NIGHT...A CHANCE OF MVFR OF LOWER CONDITIONS IN STRATUS/FOG. && .MARINE... MORNING FOG WILL SLOWLY IMPROVE AS THE DAY PROGRESSES. SEAS ARE STILL EXPECTED TO BUILD CLOSE TO 5 FT...THEREFORE SCA FOR HAZ SEAS REMAINS IN EFFECT. MARGINAL SCA SEAS ARE POSSIBLE ON THE OCEAN INTO TONIGHT...BUT WAVEWATCH IS STILL RUNNING A BIT HIGH...SO HAVE LOW CONFIDENCE IN EXTENDING THE ADVSY BEYOND TODAY. A GENERAL SOUTHERLY FLOW WILL PREVAIL TODAY THROUGH TUESDAY. SEAS SHOULD SLOWLY SUBSIDE TONIGHT AND TUESDAY...WITH MAINLY SUB SCA CONDITIONS ANTICIPATED. DUE TO THE POOR PERFORMANCE OF WAVEWATCH OVER THE LAST 2 DAYS...HAVE LOW CONFIDENCE IN ITS FORECAST DURING THE LONG TERM PERIOD. SCA FOR SEAS MAY BE NEEDED ON THE OCEAN WATERS TUE NIGHT. AS THE PRES GRADIENT INCREASES ON WED...SUSTAINED WINDS WILL INCREASE WITH SEAS LIKELY AT SCA LEVELS. A STRONG INVERSION OVER THE WATERS WILL INHIBIT WINDS ALOFT FROM MIXING DOWN...ALTHOUGH WINDS COULD REACH SCA LEVELS ON THE OCEAN THU/THU EVE. THE PRES GRADIENT RELAXES AS A COLD FRONT MOVES INTO THE WATERS THU NIGHT AND WINDS AND SEAS WILL DIMINISH BELOW SCA LEVELS THROUGH THE REST OF THE PERIOD. && .HYDROLOGY... SCATTERED SHOWERS AND TSTMS COULD PRODUCE LOCALLY HEAVY DOWNPOURS TODAY. THIS COULD LEAD TO A LOW END FLASH FLOOD THREAT. SCT SHOWERS/TSTMS TUESDAY THROUGH FRI ARE CAPABLE OF PRODUCING LOCALLY HEAVY RAINFALL...WITH AN ATTENDANT LOW END FLASH FLOOD THREAT. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR CTZ009>012. NY...DENSE FOG ADVISORY UNTIL 10 AM EDT THIS MORNING FOR NYZ071- 078>081-177-179. NJ...NONE. MARINE...DENSE FOG ADVISORY UNTIL NOON EDT TODAY FOR ANZ330-335-338-340- 345-350-353-355. SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 6 PM EDT THIS EVENING FOR ANZ350-353-355. && $$