Area Forecast Discussion
Issued by NWS Upton, NY

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000 FXUS61 KOKX 270546 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 146 AM EDT FRI MAR 27 2015 .SYNOPSIS...
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A COLD FRONT WILL PUSH WELL OFFSHORE THIS MORNING. LOW PRESSURE WILL DEVELOP OFFSHORE TONIGHT...AND TRACK TOWARDS THE MARITIMES SATURDAY. AN UPPER LEVEL DISTURBANCE MOVES ACROSS SATURDAY AND MOVES EAST OF THE REGION SATURDAY NIGHT. HIGH PRESSURE BUILDS IN THEREAFTER. FOR THE NEW WORK WEEK...A SERIES OF CLIPPER LOWS WILL BE MOVING ACROSS.
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&& .NEAR TERM /UNTIL 6 AM THIS MORNING/...
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COLD FRONT HAS PUSHED EAST OF THE REGION WITH GRADUAL CAA. POST FRONTAL SHOWER ACTIVITY WILL CONTINUE OVERNIGHT.
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&& .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/... THE FRONT EXITS THE AREA BUT THE APPROACHING UPR JET COULD SUSTAIN LGT RAIN AT LEAST INTO THE MRNG. FOCUS THEN TURNS TO DEVELOPING LOW PRES OFFSHORE AS THE H5 SHTRWV APPROACHES. THE NAM HAD HINTED AT THIS YESTERDAY...AND NOW THE GFS...ALTHOUGH THE LONE SOLN WITH THE 12Z SUITE...HAS LATCHED ON. THIS WOULD BRING PCPN IN LATE FRI AFTN/EVE...THEN SPREADING WWD FRI NGT. AT THE SAME TIME...THE PCPN WOULD TRANSITION TO SNOW OVERNIGHT AS THE COLD UPR TROF MOVES IN. WITH NLY COMPONENT FLOW...THIS CHANGEOVER WOULD OCCUR EVEN DOWN TO THE COASTS. HAVE INCLUDED CHC POPS FOR THIS EVENT...HOWEVER THE ECMWF AND NAM SOLNS WOULD LEAVE THE AREA WITH BENIGN WX. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... RELATIVELY ACTIVE WEATHER PATTERN WILL BE PRESENT FOR THE WEEKEND THROUGH EARLY NEXT WEEK. THIS IS DIAGNOSED BY SHARPER AND LESS WAVELENGTH OF TROUGHS AND CORRESPONDING RIDGES. BY MID TO LATE NEXT WEEK...THERE IS A LONGER WAVELENGTH AND HENCE CLOSER TO A ZONAL TYPE OF FLOW OCCURRING WHICH WILL BE LESS AMPLIFIED. THE MAIN UPPER JET WILL BE SOUTH OF THE REGION FOR THE WEEKEND BEFORE LIFTING BACK NORTH OVER THE AREA AND BECOMING MORE BROAD WITH LESS WIND SPEED FOR LATER NEXT WEEK. AT THE SURFACE...ONE FEATURE TO FOCUS ON IS A LOW DEVELOPING ALONG AN OFFSHORE COLD FRONT SATURDAY. THE CENTER OF THE LOW DEPENDING ON THE MODEL CHOSEN...IS APPROXIMATELY NEAR THE 40N AND 65W COORDINATES. THE GFS IS MOST PROGRESSIVE WITH THIS LOW...MOVING IT FASTER TO THE NORTHEAST INTO THE CANADIAN MARITIMES WHILE THE ECMWF...NAM...AND CMC ARE REMARKABLY SLOWER. ONCE THE LOW PUSHES FARTHER INTO THE CANADIAN MARITIMES SATURDAY NIGHT...THEN HIGH PRESSURE...ORIGINATING FROM CENTRAL CANADA...WILL GAIN MORE INFLUENCE AS IT BUILDS IN FROM THE WEST. THE RIDGE OF HIGH PRESSURE MOVES ACROSS SUNDAY AS THE CENTER OF HIGH PRESSURE MOVES INTO THE SOUTHEAST. A FAST MOVING CLIPPER LOW APPROACHES SUNDAY NIGHT...MOVING ACROSS THE REGION MONDAY. THIS WILL BE FOLLOWED BY HIGH PRESSURE MONDAY NIGHT INTO EARLY TUESDAY BEFORE ANOTHER QUICK MOVING CLIPPER LOW MOVES IN TUESDAY NIGHT. HIGH PRESSURE RETURNS BEHIND IT LEADING INTO EARLY THURSDAY BEFORE YET ANOTHER CLIPPER MOVES IN. IN TERMS OF WEATHER...OVERALL COOLER THAN NORMAL TEMPERATURES WILL CONTINUE. THIS WILL BE MOST PRONOUNCED THIS WEEKEND WITH FORECAST HIGHS ONLY REACHING THE UPPER 30S TO LOWER 40S. THERE WILL BE A FEW PERIODS TO WATCH FOR PRECIPITATION. THE HIGHEST CHANCES ARE SATURDAY BEHIND THE COLD FRONT ASSOCIATED WITH DEFORMATION TO THE WEST OF THE OFFSHORE DEEPENING LOW. QUITE THE UNCERTAINTY HERE WITH NAM AND ECMWF SHOWING LITTLE TO NO PRECIPITATION WHILE CMC AND GFS SHOW A LIGHT AMOUNT OF PRECIPITATION...GENERALLY LESS THAN A QUARTER OF AN INCH. CURRENT FORECAST TAKES INTO ACCOUNT AN AVERAGE OF ALL MODEL SOLUTIONS...WITH GENERALLY LESS THAN 1 INCH OF SNOW AND WITH TEMPERATURES ABOVE FREEZING...A LOT DEPENDS ON HOW MUCH DYNAMIC COOLING TAKES PLACE AS WELL AS THE INTENSITY OF THE SNOW AS FAR AS HOW MUCH SNOW ACCUMULATES ON THE GROUND. OTHER CHANCES FOR PRECIP WILL BE MORE IN THE NATURE OF RAIN AND SNOW SHOWERS LATE SUNDAY NIGHT INTO MONDAY AS WELL AS TUESDAY NIGHT INTO WEDNESDAY. YET ANOTHER CHANCE OF SHOWERS FOR NEXT THURSDAY. THESE ARE ALL ASSOCIATED WITH FAST MOVING CLIPPER LOWS. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/...
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A COLD FRONT...CURRENTLY THROUGH MOST TERMINALS WILL CONTINUE TO MOVE SE TODAY WITH ONLY WEAK HIGH PRESSURE BEHIND IT. RAIN/SHRA CONTINUES INTO THE MORNING PUSH WITH PRIMARILY MVFR CONDS...ALTHOUGH TEMPO VFR CONDS ARE POSSIBLE BEFORE AROUND 09Z. VFR THEN PREVAILS AFTER 13-15Z. WINDS N-NNW WITH GUSTS AT THE CITY TERMINALS UNTIL AROUND 12-14Z. WINDS THEN DIMINISH SLIGHTLY WITH NO FREQUENT GUSTS THEREAFTER. .OUTLOOK FOR 06Z FRIDAY THROUGH TUESDAY... .FRI NIGHT-SAT...CHANCE OF MVFR CONDS WITH ANY RAIN OR SNOW SHOWERS. N WINDS G15-20KT. .SAT NIGHT-.SUNDAY NIGHT...VFR. .MON...VFR. SW WINDS 15G20KT...BECOMING WNW AT NIGHT. .TUE...VFR. NW WINDS 15-20G25-30KT...DIMINISHING AT NIGHT.
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&& .MARINE...
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COLD FRONT HAS PUSHED EAST OF THE WATERS WITH SUB SCA N/NW WINDS AND IMPROVING VSBY. SCA COND REMAIN ON THE OCEAN TODAY IN HIGH SOUTHERLY SWELLS...AND WILL LIKELY NEED TO BE EXTENDED AT LEAST THRU FRI NGT. SCA POSSIBLE SATURDAY THROUGH EARLY SUNDAY AS WELL AS LATE SUNDAY NIGHT THROUGH MONDAY NIGHT. THE NEXT CHANCE FOR SCA IS TUESDAY NIGHT. THE SCA CHANCES WILL BE MAINLY ACROSS THE OCEAN AND EASTERN WATERS. OTHERWISE...SUB SCA CONDITIONS ARE FORECAST FOR THE LONG TERM FORECAST THIS WEEKEND AND NEXT WEEK OUTSIDE OF THE AFOREMENTIONED TIME PERIODS.
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&& .HYDROLOGY...
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AN ADDITIONAL 1 TO 2 TENTHS QPF THROUGH THIS AFTERNOON. NO SIGNIFICANT WIDESPREAD PRECIPITATION EXPECTED THROUGH THIS WEEKEND. CURRENTLY RIVERS AND STREAMS ARE EXPECTED TO REMAIN BELOW BANK FULL...BUT THE MILD TEMPS AND INCREASED RIVER/STREAM FLOW WILL INCREASE ICE BREAKUP AND MOVEMENT DURING THE NEXT FEW DAYS. 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.
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&& .OKX WATCHES/WARNINGS/ADVISORIES...
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CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ350- 353-355.
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&& $$ SYNOPSIS...JMC NEAR TERM...NV SHORT TERM...JMC LONG TERM...JM AVIATION...JC MARINE...NV HYDROLOGY...NV

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