Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 300646 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 246 AM EDT WED JUL 30 2014 .SYNOPSIS...
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WEAK HIGH PRESSURE WILL SLOWLY BUILD OFFSHORE THROUGH TONIGHT. A FRONTAL BOUNDARY OVER THE WESTERN ATLANTIC WILL GRADUALLY WORK WEST TOWARD THE COAST THROUGH THIS WEEKEND..WITH MULTIPLE WAVES OF LOW PRESSURE TRACKING ALONG IT. WEAK HIGH PRESSURE WILL THEN RETURN EARLY NEXT WEEK.
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&& .NEAR TERM /UNTIL 6 AM THIS MORNING/...
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STILL SEEING BKN PATCHES OF HIGH-BASED STRATOCU INLAND...ALSO IN NYC AND ALONG THE SOUTH SHORE OF LONG ISLAND. SHOWERS HAVE DEVELOPED OFFSHORE IN CONVERGENCE ZONE ASSOCIATED WITH A WEAK TROUGH. RADAR SHOWS THE ASSOCIATED CONVERGENCE BOUNDARY REMAINING OFFSHORE...SO DO NOT EXPECT ANY OF THESE SHOWERS TO DRIFT ONTO LAND. LOW TEMPS SHOULD RANGE FROM THE LOWER 50S INLAND AND IN THE LONG ISLAND PINE BARRENS...TO 60-65 IN AND NEAR NYC. DRY AIR REMAINS IN PLACE WITH DEW POINTS IN THE 50S.
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&& .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
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MODELS IN CLOSER AGREEMENT AS TO AMT OF AVAILABLE MOISTURE AND LOW LEVEL INSTABILITY THIS AFTERNOON TO LEAD TO SHOWERS AS A WEAK SHORTWAVE PASSES. 29/21Z SREF MEAN STILL SUGGESTS POSSIBILITY OF SPRINKLES IN ORANGE COUNTY FROM MID TO LATE AFTERNOON...ATTM OPTED TO KEEP FCST DRY. EVEN IF ANY SHOWERS DO MANAGE TO MAKE IT INTO ORANGE...MID LEVEL CAP SHOULD INHIBIT THUNDER. DEEPER MID LEVEL MOISTURE SHOULD SLOWLY EDGE INTO AREAS FROM NYC NORTH/WEST TONIGHT...WITH MOSTLY CLOUDY SKIES THERE AND PTCLDY TO THE EAST. FORCING FOR SHOWERS WILL BE LACKING AS SHORTWAVES PIVOTING AROUND A CLOSED UPPER LOW IN ONTARIO/QUEBEC WILL BE WEAK AND PASSING JUST TO THE NW. A BETTER AND MORE WIDESPREAD CHANCE FOR SHOWERS WILL COME ON THU AS A STRONGER SHORTWAVE PIVOTS AROUND THE CLOSED LOW...AND THERE MAY BE ENOUGH INSTABILITY TO SUPPORT AN ISOLATED TSTM PER NAM FCST SOUNDINGS. HAVE SCT COVERAGE ACROSS NEARLY THE ENTIRE CWA DESPITE ONSHORE FLOW...AS MARINE LAYER DOES NOT LOOK STRONG ENOUGH TO INHIBIT CONVECTION EXCEPT FAR ERN SECTIONS OF LONG ISLAND AND SE CT.
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&& .LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
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A HIGHLY AMPLIFIED ANOMALOUS SUMMERTIME PATTERN FEATURES A TROUGH ACROSS EASTERN NORTH AMERICA...WITH RIDGING OUT WEST AND ACROSS THE WESTERN ATLANTIC. THIS BLOCKING PATTERN WILL RESULT IN THE AFOREMENTIONED TROUGH GRADUALLY FILLING AND WORKING EAST AT THE END OF THE PERIOD AS AN UPSTREAM KICKER MOVES INTO CENTRAL CANADA. THERE ARE CLEARLY TIMING DIFFERENCES AMONGST THE GLOBAL MODEL SUITE WITH HOW QUICKLY THIS OCCURS...AS WELL AS WITH AN OFFSHORE FRONTAL BOUNDARY THAT RETROGRADES WEST IN RESPONSE TO HEIGHT RISES ALONG THE EASTERN SEABOARD THU INTO SAT. THE LATTER OF WHICH COULD BRING A BOUT OF STEADY RAINS INTO THE REGION FRI NIGHT INTO THE SAT. THE 12Z ECMWF AND 12Z GGEM REMAIN THE MOST AGGRESSIVE SOLUTIONS. THE POTENTIAL IS THERE FOE A SIGNIFICANT RAINFALL EVENT...BUT THERE REMAINS A DECENT AMOUNT OF UNCERTAINTY WITH THE LOCATION OF THE FRONTAL WAVE AND THE BOUNDARY. FOR THU INTO FRI...HIGH PRESSURE WILL BE SITUATED TO THE EAST WITH A RETURN SLY FLOW. AIR MASS REMAINS FAIRLY DRY IN THE LOW-LEVELS WITH ONLY MARGINAL INSTABILITY AND WEAK TO MODERATE SHEAR. OVERALL CHANCES FOR CONVECTION ARE LOW DURING THIS TIME WITH THE BEST CHANCES BEING IN THE AFT/EVE HOURS IN THE HILLS NW OF NYC...DRIVEN BY DIFFERENTIAL HEATING. RAIN CHANCES THEN INCREASE WITH THE APPROACH OF THE OFFSHORE FRONT AND MULTIPLE WAVES OF LOW PRESSURE. ONCE AGAIN THOUGH...THE SOLUTIONS VARY ON THE PROXIMITY OF THE FRONT. FOR EARLY NEXT WEEK...WEAK HIGH PRESSURE WILL BUILD IN ON THE HEELS OF THE DEPARTING UPPER TROUGH. THE GGEM AND GFS BOTH ARE SLOWER WITH THE PROGRESSION OF THE TROUGH. THUS...CONVECTION COULD LINGER INTO MON WITH A WEAK TROUGH/COLD FRONT MOVING THROUGH. TEMPS SHOULD BE NEAR AVG THU-FRI...THEN A LITTLE BELOW AVG THIS WEEKEND VIA CLOUD COVER AND GREATER POP...THEN RETURNING TO NEAR AVG ON MON. HUMIDITY LEVELS WILL ALSO NE ON THE INCREASE WITH DEW POINTS RISING INTO THE 60S.
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&& .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
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WEAK HIGH PRESSURE REMAINS OVER THE REGION. VFR. LIGHT AND VARIABLE WINDS OVERNIGHT...LASTING INTO WEDS MORNING. SEA BREEZES THEN DEVELOP THIS AFTERNOON AND PASS THROUGH SOME TERMINALS. WINDS GENERALLY SW TO S 10KT OR LESS. .OUTLOOK FOR 06Z THURSDAY THROUGH SUNDAY... .WEDS NIGHT...VFR. .THURSDAY-FRIDAY...ISOLATED SHOWERS/TSTMS POSSIBLE IN THE AFTERNOON/EARLY EVENING. VFR OUTSIDE OF ANY SHOWERS/TSTMS. .SATURDAY-SUNDAY...MAINLY VFR...IFR CONDITIONS POSSIBLE IN SCT SHOWERS.
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&& .MARINE... WIND AND SEAS REMAIN BELOW ADVISORY LEVELS THROUGH WEDNESDAY NIGHT. CONDITIONS SHOULD REMAIN QUIET FROM THURSDAY THOUGH EARLY NEXT WEEK WITH AN APPROACHING OFFSHORE FRONT THIS WEEKEND AND THEN WEAK HIGH PRESSURE EARLY NEXT WEEK. && .HYDROLOGY... MAINLY DRY CONDITIONS EXPECTED THROUGH WEDNESDAY NIGHT. NO SIGNIFICANT RAINFALL IS THEN EXPECTED FROM THURSDAY THROUGH FRIDAY. THERE IS THE POTENTIAL FOR HEAVY RAINFALL DURING THIS WEEKEND. TOO MUCH UNCERTAINTY AT THIS TIME FOR SPECIFICS. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...MALOIT/DW NEAR TERM...GOODMAN SHORT TERM...GOODMAN LONG TERM...DW AVIATION...LN MARINE...MALOIT/MET/DW HYDROLOGY...MALOIT/DW

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