Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 251439 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1039 AM EDT WED MAR 25 2015 .SYNOPSIS... A WARM FRONT APPROACHES TODAY AND PASSES THROUGH TONIGHT. A TRAILING COLD FRONT SLOWLY APPROACHES THURSDAY BEFORE MOVING ACROSS THURSDAY NIGHT. A SERIES OF WEAK FRONTS WILL THEN AFFECT THE REGION FRIDAY INTO SATURDAY BEHIND A DEPARTING LOW PRESSURE. HIGH PRESSURE BUILDS IN FOR SUNDAY. A FRONTAL SYSTEM MOVES THROUGH MONDAY...FOLLOWED BY HIGH PRESSURE FOR TUESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LINE OF SHOWERS CURRENTLY OVER SE PA AND INTO THE DELMARVA SLOWLY TRACKING TO THE NORTHEAST. BASED ON TIMING OF THE MOVEMENT OF THESE SHOWERS AND BASED ON LATEST RAP AND HRRR GUIDANCE...WILL PUSH BACK START TIME OF PRECIP UNTIL LATE AFTERNOON...AS SHOWERS NOT EXPECTED TO MAKE IT TO WESTERN ZONES UNTIL AFTER 18Z. OTHERWISE...CLOUDS INCREASE DURING THE DAY AS THESE SHOWERS ASSOCIATED WITH A WARM FRONT APPROACHES. A MET/MAV MOS BLEND WAS USED FOR HIGHS...AVERAGING 5-10 DEGREES BELOW NORMAL. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... THE WARM FRONT CROSSES THE CWA TONIGHT...AND WITH STRONGER LIFT RIGHT AHEAD OF IT...THE BEST OVERALL CHANCES OF OVERRUNNING/RAIN FOR THE NIGHT. WITH DEWPOINTS RISING...FOG EXPECTED AS WELL. TEMPERATURE CURVE FOR THE NIGHT NON-DIURNAL WITH WAA. WAVE OF LOW PRESSURE MOVES NE ALONG A SLOWLY MOVING COLD FRONT TO OUR WEST DURING THE DAY THURSDAY. BETTER OVERALL CHANCES OF RAIN WILL BE ROUGHLY MID-MORNING THROUGH MID-AFTERNOON WITH LIFT SUPPLIED BY A LOW LEVEL JET AND PLENTY OF MOISTURE IN PLACE. THIS LIFT...COMBINED WITH SOME ELEVATED CAPE AND MARGINALLY UNSTABLE MID LEVEL LAPSE RATES...COULD RESULT IN AN ISOLATED RUMBLE OF THUNDER AS WELL. BETTER OVERALL CHANCES OF THUNDER WOULD BE OVER THE EASTERN HALF OF THE AREA...BUT WILL LEAVE IN MENTION OF THUNDER ACROSS THE ENTIRE AREA. MAV/MET MOS WERE REASONABLY SIMILAR FOR HIGH TEMPS...SO USED A BLEND AGAIN. THE WAVE OF LOW PRESSURE PASSES JUST TO OUR NORTH THURSDAY NIGHT DRAGGING A COLD FRONT ACROSS THE AREA. WITH THE ADVECTION OF DEWPOINTS OVER 5 DEGREES WARMER THAN THE NEARBY WATER SURFACE TEMPS...THERE IS A CHANCE OF DENSE FOG DEVELOPMENT PRIMARILY OVER THE EASTERN HALF OF THE CWA AS A WEAK ONSHORE FLOW PRECEDES THE PASSAGE OF THE LOW CENTER TO THE NORTH...AND REMAIN WEAK FOR A FEW HOURS AFTERWARDS BEFORE STRENGTHENING FROM THE NORTH. RAIN IS LIKELY...FOCUSED NEAR THE COLD FRONT. ELEVATED CAPE FORECAST TO STILL BE PRESENT...SO ISO THUNDER DURING THE EVENING. && .LONG TERM /FRIDAY THROUGH TUESDAY/... GOOD MODEL AGREEMENT WITH A DEEPENING CENTRAL/EASTERN US TROUGH TONIGHT THROUGH LATE WEEK AS WESTERN US RIDGING BUILDS. THIS TROUGH WILL GRADUALLY SLIDE TO THE EAST COAST LATE WEEK INTO THE WEEKEND...BEFORE SLIDING OFFSHORE ON SUNDAY. RIDGING BRIEFLY BUILDS IN SUN NIGHT BEFORE...A NORTHERN STREAM SHORTWAVE SWINGS THROUGH THE NORTHEAST EARLY NEXT WEEK. A SLOW MOVING COLD FRONT WILL GRADUALLY SLIDE EAST OF THE REGION FRIDAY MORNING...BUT LAGGING UPPER TROUGH AND UPPER JET ENERGY...AND WEAK INVERTED SURFACE TROUGHING...IS EXPECTED TO ALLOW FOR LINGERING POST-FRONTAL RAIN BANDS TO ONLY GRADUALLY SLIDE EAST/TAPER FRIDAY MORNING INTO AFTERNOON. BASED ON SLOWER MODEL TRENDS THE LAST FEW DAYS AND BLOCKY UPPER PATTERN IT IS NOT OUT OF THE QUESTION THAT THIS ACTIVITY COULD LINGER INTO FRI NIGHT/SAT...PARTICULARLY FOR LI/CT. THIS HAS BEEN A CONSISTENT SIGNAL IN THE OPERATIONAL GFS (WEAKER SIGNAL IN GEFS)...SEEN IN 00Z OPERATIONAL GEM...WITH HINTS OF IT AT 84 HRS IN 00Z NAM. LOCATION OF ANY INVERTED TROUGH WOULD BE KEY TO WHERE MOST WIDESPREAD PRECIP ACTIVITY WOULD RESIDE DURING THIS TIME...BUT EVEN WITHOUT AN INVERTED SURFACE TROUGH FOCUS...MID- LEVEL TROUGH/COLD POOL INSTABILITY WOULD POSE A THREAT FOR AT LEAST ISOLATED DIURNAL SHOWER ACTIVITY ON SATURDAY. HAVE SLOWED DOWN TAPER OF LIKELY TO CHANCE POPS THROUGH FRIDAY...AND THEN SLIGHT CHANCE POPS THROUGH SATURDAY TO ACCOUNT FOR THIS POTENTIAL. CAA FRI NIGHT INTO SAT SHOULD ALLOW PRECIP TO MIX WITH/CHANGE TO SNOW SHOWERS FRIDAY NIGHT INTO SATURDAY MORNING...AND THEN A RAIN/SNOW MIX ON SATURDAY. TEMPS ON SATURDAY WILL LIKELY RUN ABOUT 10 TO 15 DEGREES BELOW SEASONABLE UNDER THE UPPER TROUGH AND COLD POOL. THEREAFTER...MODELS IN GENERAL AGREEMENT WITH THE UPPER TROUGH SLIDING EAST SATURDAY NIGHT INTO SUNDAY...WITH RIDGING BUILDING IN SUNDAY AND DRYING BUT COOL CONDS. THIS RESPITE WILL BE SHORT LIVED AS ANOTHER SHORTWAVE APPROACHES AND PIVOTS THROUGH THE NE EARLY NEXT WEEK WITH ASSOCIATED LOW PRESSURE SYSTEM BRING A CHANCE FOR LIGHT RAIN/SNOW SHOWER MIX. && .AVIATION /15Z WEDNESDAY THROUGH SUNDAY/... A WARM FRONT THEN APPROACHES FROM THE SOUTHWEST THIS EVENING. VFR THROUGH AT LEAST 20Z. CEILINGS DECREASE TO 3500-6000FT AFTER 19Z. MVFR CIGS ARE POSSIBLE IN ANY TEMPO -RA THAT OCCURS BETWEEN 20Z AND 00Z THU. RA BECOMES PREVAILING THEREAFTER...WITH IFR CONDITIONS AS WARM FRONT MOVES THROUGH...AND THEN LIFR...MAINLY AFTER 00Z. THERE WILL ALSO BE SOME LLWS AS A LOW LEVEL JET MOVES OVERHEAD WITH THE WARM FRONT. WINDS AT 2000 FT WILL BE AROUND 50 KT. 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: ISOLATED GUSTS OF 15-20 KT POSSIBLE IN THE AFTERNOON. MODERATE CONFIDENCE IN IFR CONDITIONS AFTER 00Z AND IFR CONDITIONS AFTER 07Z. LLWS BETWEEN 02Z- 07Z THU...WITH 50 KT WINDS AT 2000 FT. KLGA FCSTER COMMENTS: ISOLATED GUSTS OF 15-20 KT POSSIBLE IN THE AFTERNOON. MODERATE CONFIDENCE IN IFR CONDITIONS AFTER 00Z AND IFR CONDITIONS AFTER 07Z. LLWS BETWEEN 02Z- 07Z THU...WITH 50 KT WINDS AT 2000 FT. KEWR FCSTER COMMENTS: ISOLATED GUSTS OF 15-20 KT POSSIBLE IN THE AFTERNOON. MODERATE CONFIDENCE IN IFR CONDITIONS AFTER 00Z AND IFR CONDITIONS AFTER 07Z. LLWS BETWEEN 02Z- 07Z THU...WITH 50 KT WINDS AT 2000 FT. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS YELLOW...WHICH IMPLIES SLANT RANGE VISIBILITY 4-6SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: ISOLATED GUSTS OF 15-20 KT POSSIBLE IN THE AFTERNOON. MODERATE CONFIDENCE IN IFR CONDITIONS AFTER 00Z AND IFR CONDITIONS AFTER 07Z. LLWS BETWEEN 02Z- 07Z THU...WITH 50 KT WINDS AT 2000 FT. KHPN FCSTER COMMENTS: ISOLATED GUSTS OF 15-20 KT POSSIBLE IN THE AFTERNOON. MODERATE CONFIDENCE IN IFR CONDITIONS AFTER 00Z AND IFR CONDITIONS AFTER 07Z. LLWS BETWEEN 02Z- 07Z THU...WITH 50 KT WINDS AT 2000 FT. KISP FCSTER COMMENTS: ISOLATED GUSTS OF 15-20 KT POSSIBLE IN THE AFTERNOON. MODERATE CONFIDENCE IN IFR CONDITIONS AFTER 00Z AND IFR CONDITIONS AFTER 08Z. LLWS BETWEEN 03Z- 08Z THU...WITH 50 KT WINDS AT 2000 FT. .OUTLOOK FOR 12Z THURSDAY THROUGH SUNDAY... .THURSDAY...IFR OR LOWER POSSIBLE IN RAIN SHOWERS. AREAS OF FOG. LLWS POSSIBLE. .FRIDAY...MAINLY VFR WITH SMALL CHANCE OF MVFR IN ANY -SHRA. NW WINDS G15-20KT POSSIBLE. .FRIDAY NIGHT-SATURDAY...MAINLY VFR...WITH VERY SMALL CHANCE MVFR OR LOWER IN ANY -SHSN. NW WINDS G20-25KT POSSIBLE. .SATURDAY NIGHT...VFR. N-NE WINDS G15-20KT POSSIBLE. .SUNDAY...VFR. && .MARINE... HIGH PRES OVER THE AREA KEEPS TRANQUIL CONDITIONS ON THE WATERS TODAY WITH LIGHT WINDS AND SEAS 1-2 FT ON THE OCEAN AND 1 FT OR LESS ON ALL OTHER WATERS. SOUTHERLY FLOW INCREASES TONIGHT AS A WARM FRONT APPROACHES FROM THE WEST. THEN WITH INCREASING SOUTHERLY FLOW AHEAD OF A COLD FRONT...GUSTS ARE EXPECTED TO INCREASE TO SMALL CRAFT LEVELS THURSDAY AFTERNOON...PRIMARILY ON THE OCEAN WATERS...BUT POSSIBLY ON SOME OF THE OTHER WATERS. SEAS ON THE OCEAN WILL PROBABLY BUILD UP TO AT LEAST 5 FT AS WELL. WITH THIS BEING A LATE 3RD PERIOD EVENT...HAVE HELD OFF ON ISSUING SCA ATTM. THE COLD FRONT PASSES THROUGH THURSDAY NIGHT WITH AN INITIAL DROP IN WIND SPEEDS BEFORE THEY PICK UP FROM THE NORTH LATE AT NIGHT. THERE IS ALSO THE CHANCE OF DENSE FOG FORMATION ON THE WATERS THURSDAY NIGHT...SO THIS WILL NEED TO BE MONITORED. IN WAKE OF COLD FRONT...SMALL CRAFT OCEAN SEAS LIKELY REMAIN THROUGH FRIDAY WITH A GRADUAL SUBSIDE OF HIGH SOUTHERLY SWELLS. MARGINAL SCA CONDS POSSIBLE FRI NIGHT THROUGH SAT NIGHT ON THE OCEAN WITH GUSTY NW FLOW...CAA...AND RESIDUAL SOUTHERLY SWELLS. && .HYDROLOGY... 1/2 TO 1 INCH OF PRECIPITATION IS EXPECTED FROM LATE THIS AFTERNOON THROUGH FRIDAY. THE RAINFALL AND SNOW MELT WILL RESULT IN MINOR TO MODERATE RISES ON RIVERS/STREAMS ACROSS MAINLY SOUTHERN CONNECTICUT AND LOWER HUDSON RIVER VALLEY DURING THE LATE WEEK PERIOD...POSSIBLY INTO THIS WEEKEND. CURRENTLY RIVERS AND STREAMS ARE EXPECTED TO REMAIN BELOW BANKFULL...BUT THE MILD TEMPS AND INCREASED RIVER/STREAM FLOW WILL INCREASE ICE BREAKUP AND MOVEMENT DURING THE LATE WEEK PERIOD. ISOLATED ICE JAMS ARE POSSIBLE...WHICH IF THEY OCCUR...COULD RESULT IN LOCALIZED FLOODING. SINCE ICE JAM FLOODING IS UNPREDICTABLE AND SUDDEN...INTERESTS ALONG ICE COVERED RIVERS SHOULD MONITOR NWS FORECASTS FOR THE LATEST INFORMATION. FOR DETAILS ON SPECIFIC AREA RIVERS AND LAKES...INCLUDING OBSERVED AND FORECAST RIVER STAGES AND LAKE ELEVATIONS...PLEASE VISIT THE ADVANCED HYDROLOGIC PREDICTION SERVICE /AHPS/ GRAPHS ON OUR WEB SITE. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...NONE. && $$ SYNOPSIS...JC/NV NEAR TERM...JC/MPS SHORT TERM...JC LONG TERM...NV AVIATION...JMC/JP MARINE...JC/NV HYDROLOGY...JC/NV

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