Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 210807 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 407 AM EDT MON JUL 21 2014 .SYNOPSIS... HIGH PRESSURE REMAINS OVER THE AREA THROUGH TONIGHT...THEN SLIDES OFFSHORE ON TUESDAY. AS HIGH PRESSURE MOVES EAST ACROSS THE ATLANTIC OCEAN TUESDAY NIGHT...A COLD FRONT WILL MOVE SLOWLY EAST ACROSS AREA THROUGH THURSDAY. HIGH PRESSURE WILL THEN FOLLOW FROM THURSDAY NIGHT INTO THE WEEKEND. LOW PRESSURE WILL APPROACH LATE SUNDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... RIDGING BUILDS IN AT 850-700 HPA AS 500 HPA TROUGH SLOWLY EXITS TO THE EAST. AS A RESULT...SHOULD HAVE SUFFICIENT SUBSIDENCE IN THE LOW LEVELS TO KEEP THINGS DRY. MONITORING AN AREA OF STRATUS THAT CURRENTLY IS OVER FAR SE CT AND FAR EASTERN PORTIONS OF THE TWIN FORKS OF LONG ISLAND. EXPECT THIS AREA TO PUSH SLIGHTLY FARTHER WESTWARD AS BOUNDARY LAYER FLOW BECOMES EASTERLY OVER FAR EASTERN ZONES THIS MORNING. BUFKIT SOUNDINGS SUGGEST STRATUS SHOULD DISSIPATE BY LATE MORNING AS THE COLUMN WARMS ABOVE AND BELOW THE RELATIVELY THIN LAYER OF STRATUS. FOR HIGHS FOR TODAY...USED A BLEND OF MAV/MET GUIDANCE WITH NAM 2-METER TEMPERATURES AND MIXING DOWN FROM 875 HPA PER BUFKIT SOUNDINGS...WITH HIGHS NEAR TO SLIGHTLY BELOW NORMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... DEEP LAYERED RIDGE AXIS BUILDS OVER THE AREA FROM TONIGHT INTO TUESDAY...WITH THE AXIS SLIDING TO THE EAST OF AT LEAST THE NW PORTION OF THE CWA IN THE AFTERNOON. GIVEN SUBSIDENCE UNDER THE RIDGE...WENT DRY INTO TUESDAY MORNING. AFTER THAT...HAVE LIMITED POPS TO ONLY THE NW 1/3 OF THE CWA...AND THEN ONLY SLIGHT CHANCE AND MAINLY DURING TUESDAY AFTERNOON. HOWEVER WITH CAPE FORECAST TO BE MAINLY 500-1000 J/KG AND ONLY 10-15 KT OF BULK SHEAR...WOULD EXPECT ANY THUNDERSTORMS TO BE OF THE PULSE/NON- SEVERE VARIETY. FOR LOWS TONIGHT USED A BLEND OF NAM 2-METER TEMPERATURES AND MAV/MET GUIDANCE...WITH VALUES FORECAST TO BE NEAR NORMAL. FOR HIGHS TUESDAY A BLEND OF MIXING DOWN FROM 975-900 HPA PER BUFKIT SOUNDINGS...NAM 2-METER TEMPERATURES AND MAV/MET GUIDANCE WAS USED - WITH READINGS EXPECTED TO BE NEAR NORMAL. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... PREPARE FOR A CHANCE OF SHOWERS AND TSTMS MAINLY WED AFTERNOON THROUGH THE DAY THURSDAY TUE NIGHT...LIGHT SOUTH WINDS WILL CONTINUE TRANSPORTING A WARM MOIST AND UNSTABLE MARITIME TROPICAL AIR MASS ACROSS THE AREA. SFC DEW POINT TEMPS NEAR 70 DEGS WILL MAKE IT FEEL UNCOMFORTABLE. WED THROUGH THU...AN UPPER LVL SHORT WAVE AND ITS ASSOCIATED COLD FRONT WILL MOVE SLOWLY SE TOWARD AND ACROSS THE AREA. MODEL OUTPUT SHOWS DIFFERENCES IN THE AMPLITUDE AND TIMING OF THE APPROACHING SHORT WAVE WHICH WOULD RESULT IN DIFFERENCES IN WHERE AND WHEN WAVES OF LOW PRES WOULD FORM ALONG THIS COLD FRONT. AT THIS TIME...HEAVY SHOWERS AND TSTMS ARE MOST LIKELY WEST AND NORTH OF NYC MAINLY WEDNESDAY AFTERNOON THROUGH WED NIGHT. THEY ARE MOST LIKELY LATE WED NIGHT THROUGH THU ALONG THE COAST. WITH PRECIPITABLE WATER CONTENT FORECAST TO APPROACH 2 INCHES...THE MAIN THREAT WILL BE THE POTENTIAL FOR HEAVY RAIN AND ISOLATED FLASH FLOODING OF URBAN AREAS. STAY TUNED. HIGH PRESSURE IS FORECAST TO FOLLOW FRIDAY THROUGH SATURDAY. ANOTHER SHORT WAVE IS FORECAST TO APPROACH THE AREA BY LATE SUNDAY INTO MONDAY. && .AVIATION /07Z MONDAY THROUGH FRIDAY/... SURFACE RIDGE AXIS RIGHT OVER THE NYC AND LOWER HUDSON VALLEY TERMINALS EARLY THIS MORNING...WITH A LIGHT N/NE FLOW JUST EAST ACROSS THE CT/LI TERMINALS. LATEST SAT FOG IMAGERY SHOWS STRATUS JUST SOUTH OF LI...WITH THE POSSIBLE EXCEPTION BEING ACROSS PORTIONS OF FAR EASTERN LI. BASED ON THE NLY FLOW AND THE FACT THAT DEW POINTS ARE RIGHT AROUND 60...HAVE DECIDED TO LIMIT ANY MENTION OF PATCHY MVFR FOG OVERNIGHT TO KSWF. KGON IS THE NEXT POSSIBILITY...BUT HAVE LEFT OUT AT THIS TIME. WINDS WILL GRADUALLY VEER AROUND TO THE S/SE BY LATE MORNING/EARLY AFT...BUT REMAINING MOSTLY BELOW 10 KT. .OUTLOOK FOR 06Z TUESDAY THROUGH FRIDAY... .EARLY TUE AM...VFR. COASTAL IFR STRATUS POSSIBLE. .TUE PM-WED. VFR. ISOLATED TSTM NW OF THE NY METRO LATE BOTH DAYS. .WED NGT-THU...MVFR IN SCT (PERHAPS NUMEROUS) SHRA AND TSTMS AND A COLD FROPA. .FRI...VFR. && .MARINE... A RELAXED PRESSURE GRADIENT WILL KEEP WINDS TO 10 KT OR LESS AND SEAS 4 FT OR LESS ON THE OCEAN WATERS AND 1 FT OR LESS ON THE REMAINDER OF THE WATERS AROUND LONG ISLAND THROUGH TUESDAY. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT...WINDS AND SEAS WILL INCREASE APPROACHING SMALL CRAFT ADVISORY LEVELS OF 25 KT AND 5 FT WED AFTERNOON AND NIGHT. AS A COLD FRONT MOVES SLOWLY SOUTHEAST TOWARD THE AREA...SW WINDS ARE FORECAST TO INCREASE TO 15 TO 20 KT WITH GUSTS UP TO 25 KT MAINLY ACROSS THE EASTERN COASTAL WATERS WED AFTERNOON AND NIGHT. SCATTERED SHOWERS AND TSTMS ARE POSSIBLE MAINLY WED NIGHT THROUGH THURSDAY. WINDS AND SEAS ARE FORECAST TO SUBSIDE AS HIGH PRESSURE MOVES ACROSS THE REGION FRIDAY. && .HYDROLOGY... DRY INTO TUESDAY MORNING...THEN ISOLD CONVECTION COULD BRING LOCALIZED AMOUNTS UP TO A FEW TENTHS OF AN INCH TUESDAY AFTERNOON/EVENING MAINLY TO AREAS N/W OF NYC. LATE WED THROUGH THU WILL BE THE NEXT CHC OF A SIGNIFICANT RAINFALL WITH THE POTENTIAL FOR 1/4 TO 1/2 INCH WITH THE APPROACH OF A SLOW MOVING COLD FRONT. A FEW HEAVY SHOWERS AND TSTMS COULD PRODUCE BRIEF HEAVY DOWNPOURS WITH ISOLATED AMOUNTS OF UP TO AROUND 1 INCH. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...MALOIT/GC NEAR TERM...MALOIT SHORT TERM...MALOIT LONG TERM...GC AVIATION...DW MARINE...MALOIT/GC HYDROLOGY...MALOIT/GC

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