Area Forecast Discussion
Issued by NWS Upton, NY

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KOKX 211818 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 218 PM 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 THE 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/... AGAIN ONLY MINOR UPDATES NEEDED. THE SEA BREEZE PROGRESSION INLAND IS SLOWER THAN ORIGINALLY ANTICIPATED...WHICH HAS ALLOWED THE SOUTH SHORE OF NASSAU COUNTY TO HEAT FURTHER. HAVE ADJUSTED HIGH TEMPERATURES UP A DEGREE OR TWO TO ACCOUNT FOR THIS. LATEST RADAR IMAGERY /AS OF 130 PM/ SHOWS THE SEA BREEZE BEGINNING TO MOVE INLAND...WHICH SHOULD KEEP HIGH TEMPERATURES FROM RISING ABOVE THE UPPER 70S TO LOWER 80S. HIGHS WILL REMAIN NEAR TO SLIGHTLY BELOW NORMAL TODAY. OTHERWISE...A RIDGE CONTINUES TO BUILD IN THE WAKE OF AN EXITING TROUGH. SUBSIDENCE WILL GENERALLY HINDER ANY SHOWER DEVELOPMENT MAINTAINING DRY CONDITIONS ACROSS THE AREA. 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. && .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 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 /18Z MONDAY THROUGH SATURDAY/... SURFACE RIDGE HAS SHIFTED A LITTLE TOWARD THE COAST...AND HAS BEEN DELAYING SEA BREEZE INITIATION. IT ARRIVED AT KJFK A LITTLE AFTER 17Z...AND BASED ON ITS FORWARD PROGRESS PER LOCAL RADARS LOOKS TO ARRIVE AT KLGA/KEWR/KTEB BETWEEN 21Z-22Z. THE 21Z SCHEDULED AMD WILL FINE TUNE THIS TIMING. VFR WITH LIGHT S-SW FLOW TONIGHT AT MOST TERMINALS. OUTLYING TERMINALS COULD HAVE MVFR VSBY LATE TONIGHT INTO THE EARLY DAYLIGHT HOURS....AND KGON COULD FLUCTUATE BETWEEN MVFR AND IFR LATE TONIGHT AS IT OFTEN DOES AT THIS TIME OF YEAR UNDER A MOSTLY CLEAR SKY WITH LIGHT ONSHORE FLOW. VFR AFTER 12Z TUE...WITH A BETTER CHANCE FOR SEA BREEZE DEVELOPMENT AT THE USUAL TIMES...15Z KBDR/KGON...16Z JFK...AND 18Z AT KISP. ...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) KJFK FCSTER COMMENTS: HIGH CONFIDENCE. KLGA FCSTER COMMENTS: TIMING OF WIND SHIFT TO THE S MAY BE OFF BY AN HOUR. KEWR FCSTER COMMENTS: TIMING OF WIND SHIFT TO THE SE-S MAY BE OFF BY AN HOUR. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: TIMING OF WIND SHIFT TO THE SE-S MAY BE OFF BY AN HOUR. KHPN FCSTER COMMENTS: TIMING OF WIND SHIFT TO THE SE-S MAY BE OFF BY AN HOUR OR TWO. KISP FCSTER COMMENTS: TIMING OF WIND SHIFT TO THE SE-S MAY BE OFF BY AN HOUR OR TWO. .OUTLOOK FOR 18Z TUE THROUGH FRI... .TUE AFTERNOON-WED...PRIMARILY VFR. ISOLATED TSTM NW OF THE NY METRO LATE BOTH DAYS. .WED NIGHT-THU...SLOW MOVING COLD FROPA. BRIEF MVFR OR LOWER CONDS IN SCT-NUMEROUS SHOWERS/TSTMS. .FRI-SAT...VFR. && .MARINE... A RELAXED PRESSURE GRADIENT WILL KEEP WINDS TO 15 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 SEAS 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...GC/MALOIT NEAR TERM...GC/MALOIT SHORT TERM...MALOIT LONG TERM...GC AVIATION...GOODMAN MARINE...GC/MALOIT HYDROLOGY...GC/MALOIT

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.