Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 070552 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 152 AM EDT TUE JUL 7 2015 .SYNOPSIS... A DIFFUSE WARM FRONT GRADUALLY MOVES NORTH INTO THE REGION THROUGH TUESDAY. A COLD FRONT MOVES ACROSS THE REGION ON WEDNESDAY...FOLLOWED BY A SERIES OF LOW PRESSURE SYSTEMS. HIGH PRESSURE RETURNS FOR THE END OF THE WORK WEEK AND INTO THE WEEKEND WITH A RETURN TO UNSETTLED WEATHER FOR THE START OF NEXT WEEK. && .NEAR TERM /THROUGH TODAY/... SOME SLIGHT ADJUSTMENTS WERE MADE TO TEMPERATURES BY INCREASING THEM BY 1-2 DEGREES FOR SOME LOCATIONS ALONG WITH LOWERING POPS FOR SHOWERS AS WELL AS REDUCING THE TIME WINDOW FOR PATCHY FOG. THERE IS A LITTLE MORE OF A TEMP AND DEWPOINT SPREAD TO OVERCOME. OTHERWISE...NO OTHER REMARKABLE CHANGES MADE TO THE FORECAST DATABASE. WARM FRONT LIES ACROSS SOUTH-CENTRAL NJ AND IS LIFTING TO THE NORTH. CAN BE NOTED BY SLIGHTLY WARMER TEMPS/DEWPOINTS...BUT MARITIME TROPICAL AIRMASS SPREADS ALONG THE COAST AND INTO THE LOCAL AREA WITH SFC DEWPOINTS AROUND 70. TEMPERATURES AT SOME LOCATIONS EVEN INCREASED BY ONE DEGREE OVER THE PAST HOUR. HAVE CONFINED ANY MENTION OF POPS TO FAR WESTERN ZONES OVERNIGHT. SOME FOG IS POSSIBLE WITH THE MOIST ONSHORE FLOW. USED "PATCHY" WORDING AS COVERAGE LOOKS TO BE MORE LIMITED WITH A FEW DEGREES OF TEMP AND DEWPOINT SPREAD. THE POSSIBLE EXCEPTION IS THE SOUTH SHORE OF LONG ISLAND. NARRE-TL IS POINTING FOR THE JERSEY COAST. WITH IT BEING CLIMATOLOGICALLY UNFAVORABLE FOR FOG...WILL HOLD OFF ON ANYTHING MORE THAN PATCHY. FROM OBSERVATIONS...LOOKS LIKE THIS IS SHAPING TO BE MORE OF A LOW STRATUS VERSUS FOG EVENT. && .SHORT TERM /TONIGHT THROUGH 6 PM WEDNESDAY/... WARM AND HUMID WITH SIGNIFICANT CLOUD COVER. WITH A MARITIME TROPICAL AIR MASS OVER THE REGION, THE APPROACH OF THE WEAKENING SHORT WAVE CONTINUES TO HAVE THE POTENTIAL TO GENERATE SHOWERS AND AN ISOLATED TSTM...ESPECIALLY TUESDAY AFTERNOON. THE HIGHEST POPS ARE NW WHERE NWP AND 15Z SREF MEAN ARE FOCUSED. INSTABILITY IS BETTER THAN TODAY WITH FORECAST SFC BASED CAPES OF 500-1500 J/KG (HIGHEST IN GFS). FCST HIGHS SHOULD BE A FEW DEGREES ABOVE NORMAL AND ARE CLOSE TO THE SLIGHTLY WARMER NAM MOS. THERE IS A MODERATE RISK FOR RIP CURRENTS AT OCEAN BEACHES ON TUESDAY. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... COLD FRONT SLOWLY WORKS ITS WAY ACROSS THE AREA WEDNESDAY AND SHOULD BE SOUTH OF THE REGION BY WEDNESDAY EVENING. THERE WILL BE ABUNDANT LOW LEVEL MOISTURE ACROSS THE REGION WITH SFC DEW POINTS AROUND 70 AND PWATS OVER 2". AS A RESULT...CAN EXPECT HEAVY RAIN AT TIMES...AND WITH TRAINING OF CELLS...AT LEAST MINOR URBAN/SMALL STREAM FLOODING IS POSSIBLE. THERE IS LITTLE CONSENSUS AMONG THE MODELS AS TO TIMING AND STRENGTH OF STORMS...SO WILL KEEP POPS CAPPED AT CHANCE FOR NOW WITH NEST CHANCES IN THE AFTERNOON/EVENING. 12Z NAM HAS LITTLE QPF OVER THE AREA...GENERALLY LESS THAN 1/4"...WHILE THE 12Z ECMWF IS SIMILAR IN TERMS OF LESS THAN 1/4" WIDESPREAD QPF...AREAL COVERAGE IS MORE WIDESPREAD THAN THE NAM. THE 12Z GFS DEVELOPS SFC LOW PRES OVER THE DELMARVA WEDNESDAY EVENING...AND IF IT WERE TO TRACK CLOSE ENOUGH TO SOUTHERN PORTIONS OF NE NJ...NYC...AND LONG ISLAND...THOSE AREAS COULD PICK UP AROUND AN INCH WEDNESDAY NIGHT WHILE THE OTHER MODELS HAVE THE REGION DRYING OUT. MAINLY...THIS APPEARS TO BE DUE TO A STRONG H5 SHORTWAVE NOTED IN THE GFS PASSING THROUGH THE REGION...WHILE THE ECMWF HAS A WEAKER SHORTWAVE MUCH FARTHER SOUTH. THIS IS A FLUID SITUATION...AND FURTHER MODEL RUNS WILL BE NEEDED. CONDS DRY OUT BY THURSDAY MORNING...BUT THEN ANOTHER WAVE OF LOW PRES MOVES THROUGH THE REGION IN THE AFTERNOON...TOUCHING OFF SOME MORE SHOWERS/STORMS IN THE AFTERNOON/EVENING. HIGH PRES THEN BUILDS IN THEREAFTER WITH DRY CONDS FOR THURSDAY THROUGH SUNDAY. TEMPS WILL BE MILD WITH HIGHS GENERALLY IN THE 80S AND LOWS IN THE UPPER 60S/LOW 70S. THE HIGH MOVES OFFSHORE ON SUNDAY...AND THE NEXT WAVE OF LOW PRES APPROACHES FOR SUNDAY NIGHT/MONDAY. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... A WARM FRONT APPROACHES FROM THE SOUTHWEST OVERNIGHT AND LIFTS NORTH OF THE REGION TODAY. OVERNIGHT...MVFR CONDITIONS LOWER TO IFR. SOME LIFR CONDITIONS POSSIBLE...WITH BEST CHANCES AT KGON...ISP AND KBDR. CHANCE OF SHOWERS FROM 13Z-20Z TODAY...ESPECIALLY ALONG AND W OF A KLGA-KSWF LINE. CHANCE OF THUNDER IS ALSO POSSIBLE...HOWEVER CHANCES ARE TOO LOW TO INCLUDE IN THE TAF AT THIS TIME. WINDS WILL BE OUT OF THE SE...GENERALLY 10 KT OR LESS THROUGH MIDDAY. THIS AFTERNOON...SOME GUSTS INTO THE TEENS OR EVEN LOWER 20 KT POSSIBLE EAST OF NYC. .OUTLOOK FOR 06Z WED THROUGH SAT... .TUE NIGHT...MVFR/IFR CONDS POSSIBLE. .WED...SHRA/TSTMS POSSIBLE WITH MVFR OR LOWER CONDITIONS AT TIMES. .THU-FRI...CHANCE OF SHOWERS WITH MVFR OR LOWER CONDITIONS AT TIMES. .SAT...VFR. && .MARINE... RATHER TRANQUIL THROUGH TUESDAY...THOUGH WINDS ARE EXPECTED TO INCREASE. FOG COULD AFFECT THE WATERS LATE TONIGHT AND TUESDAY MORNING ALONG THE SOUTH SHORE OF LONG ISLAND WITH VISIBILITY REDUCED TO 1 TO 3 NM...AND POSSIBLY BELOW 1 NM AT TIMES. A COLD FRONT MOVES ACROSS THE WATERS ON WEDNESDAY...FOLLOWED BY A SERIES OF LOW PRESSURE WAVES THROUGH THURSDAY NIGHT. THIS WILL KEEP AT LEAST A CHANCE FOR SHOWERS/TSTMS IN THE FORECAST. HIGH PRES BUILDS IN FOR THE END OF THE WEEK AND THE WEEKEND WITH DRY CONDS. THE GRADIENT OVER THE WATERS SHOULD REMAIN RELAXED ENOUGH TO KEEP CONDS BELOW SCA LEVELS DURING THIS TIME. && .HYDROLOGY... SUMMER CONVECTION IS FCST FOR TUESDAY AND WEDNESDAY (MORE LIKELY) AFTNS. WITH PRECIPITABLE WATER VALUES NEAR 2 INCHES...HEAVY RAINFALL IS POSSIBLE. WITH THE CONVECTION ALSO BEING RATHER SLOW MOVING...LOCALIZED URBAN AND POOR DRAINAGE FLOODING COULD OCCUR...WITH A LOW PROBABILITY OF FLASH FLOODING. THIS HAZARDS IS HIGHLIGHTED IN THE HAZARDOUS WEATHER OUTLOOK TEXT PRODUCT FROM FAIRFIELD AND NASSAU COUNTIES ON WEST...INCLUDING NYC FOR WEDNESDAY AFTERNOON AND EVENING. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...MPS/TONGUE NEAR TERM...JM/JP/TONGUE SHORT TERM...TONGUE LONG TERM...MPS AVIATION...BC MARINE...MPS/TONGUE HYDROLOGY...MPS/TONGUE

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