Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 291452 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 952 AM EST THU JAN 29 2015 .SYNOPSIS... HIGH PRESSURE OVER THE AREA THIS MORNING WILL SLIDE OFFSHORE TODAY. AN AREA OF LOW PRESSURE WILL APPROACHES FROM THE WEST THURSDAY EVENING...THEN CROSSES THE AREA LATE THURSDAY NIGHT AND FRIDAY...IMMEDIATELY FOLLOWED BY AN ARCTIC COLD FRONT. LOW PRESSURE DEEPENS AS IT DEPARTS TO THE EAST FRIDAY NIGHT. HIGH PRESSURE BUILDS SATURDAY. A WEAK COLD FRONT MOVES THROUGH ON SUNDAY. LOW PRESSURE MOVES OUT OF THE MISSISSIPPI VALLEY AND TRACKS TO THE SOUTH MONDAY. HIGH PRESSURE FOLLOWS INTO MID WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... HIGH CLOUDS BEGINNING TO MOVE IN FROM THE WEST AS RIDGE OVER THE REGION SLIDES OFF SHORE...AND CONTINUES MOVING EAST THROUGH THIS AFTERNOON. RETURN FLOW SETS UP AND BOTH TEMPERATURES AND DEW POINTS RISE THROUGH MUCH OF THE DAY. JUST SOME MINOR ADJUSTMENTS TO THE GRIDS FOR CURRENT CONDITIONS. HIGH TEMPERATURES LOOK TO STILL BE ON TARGET. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/... FAIRLY HIGH CONFIDENCE IN THE SHORT TERM AS A CLIPPER SYSTEM MOVES ACROSS THE REGION TONIGHT AND FRIDAY. THERE IS SOME UNCERTAINTY WITH TEMPERATURES. THINKING THAT LATEST MAV/MET GUIDANCE IS A BIT TOO WARM...SO CUT TEMPERATURES A DEGREE OR TWO...ESPECIALLY WITH A SNOWPACK ACROSS THE MUCH OF THE AREA. WILL CONTINUE TO GO WITH SNOW JUST ABOUT EVERYWHERE - THOUGH EXPECT A WET SNOW FOR THE COAST. SNOWFALL TOTALS WILL RANGE FROM 1 TO 2 INCHES ACROSS THE ENTIRE CWA. 1 INCH CLOSER TO THE COAST AND 2 FURTHER NORTH AND WEST OF NYC. THE CLIPPER PULLS AN ARCTIC FRONT ACROSS THE REGION WITH A MASSIVE DROP IN TEMPERATURES DURING THE LATE AFTERNOON. IT WILL BECOME WINDY BY LATE AFTERNOON...DROPPING WIND CHILLS INTO THE SINGLE DIGITS OVER WESTERN ZONES AND TEENS AND LOWER 20S OVER EASTERN ZONES. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... GLOBAL MODELS ARE IN GENERAL AGREEMENT ON TROUGH CLOSING OFF AS IT TRAVERSES JUST TO THE EAST FRIDAY NIGHT. NOT A LOT OF CHANGE IN THE UPPER FLOW AS CLOSED LOW REMAINS OVER HUDSON BAY...WITH DEEP TROUGH OVER THE ATLANTIC. MEAN TROUGH REMAINS FROM THE CENTRAL STATES EASTWARD. RIDGE OUT WEST FLATTENS SOMEWHAT IN TIME. AT THE SURFACE...LOW PRESSURE DEEPENS OVER THE GULF OF MAINE AS IT MOVES SLOWLY EAST. HIGH PRESSURE MOVES OUT OF THE UPPER MID WEST TOWARD THE OHIO VALLEY FRIDAY NIGHT. IN BETWEEN...VERY TIGHT PRESSURE GRADIENT IS IN PLACE ACROSS THE NORTHEAST. THE HIGH MOVES WELL TO THE SOUTH...WITH A WEAK FRONT BETWEEN ANOTHER HIGH TO THE NORTH. THIS FRONT MOVES THROUGH SOMETIME SUNDAY...WITH LITTLE FANFARE. THEN ATTENTION TURNS TO LOW PRESSURE THAT TRACKS ACROSS THE LOWER MISS VALLEY SUNDAY. ANALYSIS OF VARIOUS MODEL TRACKS WOULD PUT THE LOW OFF THE MID ATLANTIC STATES SOMETIME MONDAY...WITH GGEM MUCH SLOWER. SOLUTIONS FROM RUN TO RUN CONTINUE TO WAFFLE AND UNCERTAINTY EXISTS. VARIOUS SOURCES OF ENERGY IN THE SHORT TERM DO NOT REACH WESTERN CANADA UNTIL FRIDAY...SO IT MAY TAKE UNTIL AT LEAST LATE FRIDAY FOR POSSIBLE SOLUTIONS TO CONVERGE HOPEFULLY. WILL THUS NOT STRAY FAR FROM PREVIOUS FORECAST...BUT WILL INTRODUCE POPS SUNDAY NIGHT AND CONTINUE INTO MONDAY. COLD AIR WILL PREVAIL. DANGEROUSLY COLD FRIDAY NIGHT COURTESY OF STRONG COLD AIR ADVECTION AND STRONG NW WINDS. IN FACT...WINDS MAY REACH ADVISORY CRITERIA FOR PORTIONS OF THE AREA...AND THESE WINDS ALONG WITH PLUMMETING TEMPS WILL YIELD BELOW ZERO WIND CHILL READINGS. NW ZONES LIKELY APPROACH WIND CHILL ADVISORY CRITERIA OF -15. ANOTHER ROUND OF DANGEROUSLY COLD TEMPS ARRIVES BEHIND THE MONDAY NIGHT SYSTEM. LEANED TOWARD WPC NUMBERS...WITH SOME WEIGHT TO PREVIOUS FORECAST. && .AVIATION /15Z THURSDAY THROUGH MONDAY/... HIGH PRESSURE SLIDES OFFSHORE TODAY. LOW PRESSURE APPROACHES FROM THE WEST THIS EVENING...THEN BEGINS TO CROSS THE AREA OVERNIGHT. VFR TODAY. MVFR LIKELY DEVELOPS AFTER 00Z JUST AHEAD OF LIGHT SNOW. THEN IFR IN LIGHT SNOW FROM AROUND/JUST AFTER MIDNIGHT THROUGH REMAINDER OF TAF PERIOD. LIGHT AND VARIABLE WINDS INTO EARLY AFTERNOON...WHERE BECOME SE AT LESS THAN 10 KT AT CITY TERMINALS. WINDS THEN VEER TO THE S THIS EVENING...REMAINING LIGHT AND VARIABLE INLAND. HIGH CONFIDENCE IN OCCURRENCE OF WINDS AS DESCRIBED ABOVE AND DEVELOPMENT OF MVFR CONDITIONS. MODERATE CONFIDENCE IN IFR. CONFIDENCE IN EXACT TIMING IS LOWER. 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: TIMING OF CHANGES IN WIND SPEED AND DIRECTION AND CHANGES IN FLIGHT CATEGORIES COULD BE OFF +/- 2-3 HOURS. KLGA FCSTER COMMENTS: TIMING OF CHANGES IN WIND SPEED AND DIRECTION AND CHANGES IN FLIGHT CATEGORIES COULD BE OFF +/- 2-3 HOURS. KEWR FCSTER COMMENTS: TIMING OF CHANGES IN WIND SPEED AND DIRECTION AND CHANGES IN FLIGHT CATEGORIES COULD BE OFF +/- 2-3 HOURS. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: TIMING OF CHANGES IN WIND SPEED AND DIRECTION AND CHANGES IN FLIGHT CATEGORIES COULD BE OFF +/- 2-3 HOURS. KHPN FCSTER COMMENTS: TIMING OF CHANGES IN WIND SPEED AND DIRECTION AND CHANGES IN FLIGHT CATEGORIES COULD BE OFF +/- 2-3 HOURS. KISP FCSTER COMMENTS: TIMING OF CHANGES IN WIND SPEED AND DIRECTION AND CHANGES IN FLIGHT CATEGORIES COULD BE OFF +/- 2-3 HOURS. .OUTLOOK FOR 12Z FRI THROUGH MON... .FRIDAY MORNING...IFR CONDITIONS LIKELY IN -SN. SNOW ACCUMULATION OF ABOUT AN INCH LIKELY...PERHAPS UP TO 2 INCHES AT KHPN/KSWF. .FRIDAY AFTERNOON...CHANCE MVFR IN -SN. NW WINDS G20-25 KT LIKELY. .FRIDAY NIGHT-SATURDAY...VFR. NW WINDS G30-35KT LIKELY. .SATURDAY NIGHT-SUNDAY...VFR. .SUNDAY NIGHT-MONDAY..IFR POSSIBLE IN SNOW. && .MARINE... SUB-SCA CONDITIONS EXPECTED TODAY AS HIGH PRESSURE MOVES ACROSS THE WATERS. WINDS SHIFT AROUND TO THE SOUTH AS THE HIGH MOVES EAST. WINDS AND SEAS START TO INCREASE LATE TONIGHT IN RESPONSE TO A TIGHTENING PRESSURE GRADIENT. EXPECT SMALL CRAFT ADVISORIES ON THE OCEAN WATER TONIGHT STARTING AT 6Z. A CLIPPER SYSTEM MOVING NORTH OF THE WATERS WILL DRAG AN ARCTIC FRONT ACROSS THE WATERS ON FRIDAY. WINDS RAPIDLY INCREASE LATE FRIDAY. EXPECT GALE FORCE GUSTS TO START TO DEVELOP AFTER 18Z FRIDAY. AS LOW PRESSURE DEEPENS TO THE EAST AND HIGH PRESSURE BUILDS TO THE WEST...STRONG GALES ARE EXPECTED FRIDAY NIGHT INTO SATURDAY MORNING. IN FACT...SOME GUSTS COULD APPROACH STORM FORCE. OVERALL THOUGH GUSTS OF 35 TO 45 KT ARE EXPECTED. VERY COLD TEMPS WILL RESULT IN FREEZING SPRAY FRIDAY NIGHT INTO SATURDAY. WINDS DIMINISH SLOWLY LATER SATURDAY AND SATURDAY NIGHT AS HIGH PRESSURE PASSES WELL SOUTH AND A WEAK FRONT APPROACHES FROM THE NORTH. ANOTHER AREA OF LOW PRESSURE IS EXPECTED TO APPROACH LATE SUNDAY AND MOVE JUST SOUTH OF THE WATERS MONDAY. WINDS INCREASE BEHIND THIS LOW. ROUGH SEAS FRIDAY NIGHT AND SATURDAY WILL GRADUALLY SUBSIDE WITH THE DIMINISHING WINDS. SEAS BUILD AGAIN MONDAY. && .HYDROLOGY... NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH FRIDAY...THOUGH SOME LIGHT SNOW IS EXPECTED TONIGHT INTO FRIDAY...WITH NO HYDROLOGIC IMPACT EXPECTED. THERE IS THE POTENTIAL FOR SIGNIFICANT PRECIPITATION IN THE FORM OF SNOW...OF AT LEAST 1/2 INCH LIQUID EQUIVALENT SUNDAY NIGHT AND MONDAY. HOWEVER...MUCH UNCERTAINTY EXISTS AS THE STORM MAY PASS FAR ENOUGH TO THE SOUTH FOR LITTLE OR NO PRECIPITATION. STAY TUNED. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...GALE WARNING FROM 1 PM FRIDAY TO 6 AM EST SATURDAY FOR ANZ330- 335-338-340-345-350-353-355. SMALL CRAFT ADVISORY FROM 1 AM TO 1 PM EST FRIDAY FOR ANZ350- 353-355. && $$ SYNOPSIS...BC/PW NEAR TERM...MET/PW/BC SHORT TERM...BC LONG TERM...PW AVIATION...MALOIT/GOODMAN MARINE...BC/PW HYDROLOGY...BC/PW

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