Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 290907 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 407 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 AM THIS MORNING/... HIGH PRESSURE OVER THE REGION THIS MORNING...SLIDES OFFSHORE THROUGH THE DAY. EXPECT DRY CONDITIONS. EXPECT AN INCREASE IN MID AND HIGH LEVEL CLOUDS MOVING IN FROM THE WEST TODAY...AS A LOW PRESSURE SYSTEM AND ASSOCIATED MID LEVEL SHORTWAVE APPROACHES FROM THE WEST. HIGH TEMPERATURES TODAY CLIMB INTO THE UPPER 20S TO LOWER 30S. STAYED CLOSE TO A MOS BLEND TODAY. && .SHORT TERM /6 AM THIS MORNING 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 SFC...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 DEVELOPS OVER THE SW STATES...TRACKING 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 CAA 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 /09Z THURSDAY THROUGH MONDAY/... A HIGH PRESSURE RIDGE WILL MOVE OVERHEAD TODAY...THEN SLIDE TO THE EAST TONIGHT AS DEVELOPING LOW PRESSURE APPROACHES. VFR THROUGH MUCH OF THE DAY...THEN THERE IS INCREASING POTENTIAL FOR MVFR CIGS TO DEVELOP AFTER 21Z ACROSS NYC/NJ AND WESTERN TERMINALS. IFR CONDS AS POSSIBLE IN LIGHT SNOW AS EARLY AS 00Z... WITH INCREASING PROBABILITIES THEREAFTER THROUGH 06Z. N WINDS UNDER 10 KT WILL BECOME VRB AROUND 5 KT MID TO LATE MORNING...THEN MAINLY SE FLOW UNDER 10 KT WILL DEVELOP AND LAST INTO EVENING. A PERIOD OF GUSTS CLOSE TO TO 20 KT IS POSSIBLE CITY/COAST. ...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 THROUGH THIS AFTERNOON. KLGA FCSTER COMMENTS: HIGH CONFIDENCE THROUGH THIS AFTERNOON. KEWR FCSTER COMMENTS: HIGH CONFIDENCE THROUGH THIS AFTERNOON. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: HIGH CONFIDENCE THROUGH THIS AFTERNOON. KHPN FCSTER COMMENTS: HIGH CONFIDENCE THROUGH THIS AFTERNOON. KISP FCSTER COMMENTS: HIGH CONFIDENCE THROUGH THIS AFTERNOON. .OUTLOOK FOR 06Z FRI THROUGH MON... .LATE TONIGHT-FRI MORNING...IFR CONDITIONS LIKELY IN LIGHT SNOW. SNOW ACCUMULATION OF ABOUT AN INCH LIKELY...PERHAPS UP TO 2 INCHES AT KHPN/KSWF. .FRI AFTERNOON...STILL A CHANCE OF LIGHT SNOW WITH MVFR CONDS. NW WINDS INCREASING TO 15G20-25 KT AS THE LOW BEGINS TO INTENSIFY WHILE MOVING OFF THE NEW ENGLAND COAST. .FRI NIGHT-SAT...VFR. NW WINDS 20-25G30-35KT...DIMINISHING LATE IN THE AFTERNOON. .SAT NIGHT-SUNDAY...VFR WITH HIGH PRESSURE PASSING OHD. .SUNDAY NIGHT-MON...CHANCE OF SNOW WITH IFR CONDS AS LOW PRESSURE PASSES TO THE SOUTH. && .MARINE... SUB-SCA CONDITIONS EXPECTED TODAY. 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 KTS 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 THURSDAY NIGHT 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...BC SHORT TERM...BC LONG TERM...PW AVIATION...GOODMAN MARINE...BC/PW HYDROLOGY...BC/PW

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