Area Forecast Discussion
Issued by NWS Upton, NY

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844 FXUS61 KOKX 110250 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 950 PM EST WED FEB 10 2016 .SYNOPSIS... LOW PRESSURE EAST OF NEW ENGLAND THIS EVENING WILL GRADUALLY LIFT NORTHEAST ACROSS THE CANADIAN MARITIMES THROUGH THURSDAY...WHILE POLAR HIGH PRESSURE BUILDS EAST FROM THE MIDWEST. A WEAK TROUGH OF LOW PRESSURE WILL PASS THROUGH THE AREA THURSDAY AFTERNOON. A STRONG ARCTIC COLD FRONT WILL THEN APPROACH FRIDAY NIGHT AND PASS THROUGH SATURDAY MORNING AS A DEVELOPING OCEAN STORM PASSES BY TO THE SOUTHEAST. STRONG ARCTIC HIGH PRESSURE WILL BUILD ACROSS LATER SATURDAY INTO SUNDAY NIGHT...THEN RETREAT TO THE NORTHEAST MONDAY INTO MONDAY NIGHT. A LOW PRESSURE SYSTEM FOLLOWS FOR THE MID-WEEK PERIOD. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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MINOR ADJUSTMENTS MADE TO FORECAST BASED ON CURRENT CONDITIONS. LIGHT SNOW IS FALLING ACROSS WESTERN/CENTRAL PA IN ASSOC WITH THE THE APPROACHING UPPER TROUGH. THERE IS SOME UNCERTAINTY AS TO HOW MUCH OF THIS ACTIVITY WILL MAKE IT EAST OF THE RIDGES LATER TONIGHT WITH A MODERATE WESTERLY. SHORT WAVE RIDGING ALOFT WILL BRIEFLY BUILD ACROSS THE AREA THIS EVENING WHICH WILL RESULT IN PARTIAL CLEARING. THE UPPER TROUGH AXIS TO THE WEST THOUGH WILL APPROACH LATER TONIGHT WITH DECENT LIFT IN THE LOW TO MID LEVELS AND A NEARLY SATURATED 850-700 MB LAYER. THIS SHOULD PRODUCE SCT SNOW SHOWERS AND/OR FLURRIES ACROSS THE REGION DURING THE OVERNIGHT. A DUSTING IS POSSIBLE ACROSS THE REGION. GRADUAL COLD ADVECTION WILL CONTINUE THROUGH THE NIGHT WITH THE UPPER TROUGH MOVING ACROSS THE AREA. OVERNIGHT LOWS WILL BE IN THE UPPER TEENS TO THE LOWER 20S. WIND CHILL VALUES WILL DROP TO AROUND 10.
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&& .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... UPPER TROUGH AXIS LIFTS NE ACROSS THE REGION ON THU AND PASSES TO THE NE BY EVENING. DEEP-LAYERED CYCLONIC FLOW AND STEEP MID- LEVEL LAPSE RATES WILL RESULT IN SCT SNOW SHOWERS THROUGH THE DAY. THE MOST LIKELY TIME WOULD BE DURING THE LATE MORNING AND AFTERNOON WHEN SFC BASED INSTABILITY IS THE GREATEST. A TIGHT PRESSURE GRADIENT BETWEEN DEPARTING LOW PRESSURE OVER THE CANADIAN MARITIMES AND HIGH PRESSURE BUILDING EAST FROM THE MIDWEST WILL RESULT IN WIND GUSTS UP TO 30 MPH...POSSIBLY HIGHER DURING THE EARLY EVENING HOURS WITH THE PASSAGE OF A SFC TROUGH. COLD ADVECTION WILL CONTINUE WITH 85H TEMPS APPROACHING -20 DEG C BY EVENING. WINDS BEGIN TO RELAX LATE THU NIGHT AS HIGH PRESSURE BUILDS OVER THE MID ATLANTIC STATES. SKIES WILL CLEAR THU EVENING. HIGHS THU WILL BE 25 TO 30...AND LOWS THU NIGHT WILL BE IN THE SINGLE DIGITS INLAND AND IN THE LOWER TO MID TEENS AT THE COAST. THESE READINGS WILL BE 10-15 DEGREES BELOW NORMAL. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... FRIDAY BEGINS WITH FAIR CONDITIONS WITH WEAK SURFACE RIDGING AND A ZONAL FLOW ALOFT. THE ATMOSPHERIC COLUMN BEGINS TO MOISTEN ALOFT AHEAD OF SHORTWAVE ENERGY ROUNDING THE PERIPHERY OF A DEEP UPPER TROUGH/POLAR VORTEX. WITH THE LACK OF COMBINED LIFT AND SUFFICIENT MOISTURE...WILL GO WITH A DRY FORECAST. A MAV/NAM MOS BLEND LOOKED GOOD FOR HIGH TEMPS...WHICH WILL BE BELOW NORMAL. AN ARCTIC COLD FRONT THEN APPROACHES FRIDAY NIGHT ALONG WITH THE SHORTWAVE FROM THE NORTH. AT THE SAME TIME...SHORTWAVE ENERGY MOVES OFF THE MID ATLANTIC COAST. THE COMBINED ENERGY SHOULD INITIATE SFC CYCLOGENESIS ALONG A BAROCLINIC ZONE TO OUR SOUTH WITH THE LOW PASSING WELL SE OF THE 40N/70W BENCHMARK LATE AT NIGHT. LOOKS LIKE ANY CHANCE OF SNOW DIRECTLY ASSOCIATED WITH THIS LOW LOOKS LOW...HOWEVER...WITH THE ARCTIC FRONT AND DECREASING STABILITY DUE TO CYCLONIC FLOW ALOFT...SCT SNOW SHOWERS EXPECTED. WILL CAP POPS AT CHC FOR NOW. AN ANOMALOUSLY COLD AIR MASS THEN POURS IN BEHIND THE COLD FRONT FOR THE WEEKEND. ANOTHER SHORTWAVE ARRIVES ALONGSIDE THE CORE OF COLD AIR ALOFT DURING SAT/SAT EVENING. THE ATMOSPHERIC COLUMN DRIES...HOWEVER THERE IS STILL AT LEAST A CHANCE OF FLURRIES DURING THIS PERIOD. AS FOR TEMPS SAT AND SAT NIGHT...THE CALENDAR DAY HIGH TEMP ON SATURDAY WILL PROBABLY OCCUR DURING THE PRE-DAWN HOURS AS STRONG COLD ADVECTION DROPS TEMPS THROUGHOUT THE DAY. BY NOON...TEMPS ARE PROBABLY IN THE TEENS AREA-WIDE WITH WIND CHILL VALUES BELOW ZERO. RECORD TO NEAR-RECORD COLD TEMPS FOR SAT NIGHT IN SPITE OF GUSTY NW FLOW. BOTH GFS AND ECMWF SHOW 850MB TEMPS DROPPING TO -29C TO -30C DURING THE NIGHT BEFORE RISING A FEW DEGREES TOWARD DAYBREAK. BASED ON TEMPS THAT OCCURRED DURING A SIMILAR SYNOPTIC SETUP LAST FEBRUARY WITH WARMER TEMPS ALOFT...WENT SLIGHTLY BELOW THE LOW TEMPS THAT HAD OCCURRED...WHICH ARE CLOSE TO WHAT ECMWF MOS HAS BEEN SHOWING FOR THE PAST FEW RUNS. SEE THE CLIMATE SECTION BELOW FOR MORE DETAILS. THE COLD AIR COMBINED WITH WINDS WOULD PRODUCE WIND CHILLS THAT WOULD WARRANT AN ADVISORY DURING SAT NIGHT INTO SUNDAY MORNING...POSSIBLY EVEN A WARNING FOR SOME OF THE NORTHERN SUBURBS. REMAINING COLD BUT DRY ON SUNDAY AS HIGH PRESSURE BUILDS IN WITH HIGHS ONLY IN THE TEENS. MODELS THEN IN DISAGREEMENT WITH THE TIMING OF THE NEXT SYSTEM TO POTENTIALLY AFFECT THE REGION. HIGH PRESSURE SHIFTS OFFSHORE ON MONDAY WITH THE LIKELIHOOD THAT THE DAYTIME HOURS REMAIN DRY. A LONGWAVE TROUGH THEN SHIFTS THROUGH THE EASTERN HALF OF THE U.S. WITH ITS AXIS PROGGED TO MOVE THROUGH DURING TUESDAY NIGHT. THIS THEN HELPS STRENGTHEN A SURFACE LOW MOVING UP THE VICINITY OF THE EASTERN SEABOARD. LOW CONFIDENCE IN THE EVOLUTION...TRACK AND TIMING OF THIS SYSTEM...AND CONSEQUENTLY PCPN TYPE. HAVE CAPPED POPS AT 50 PERCENT FOR THE REST OF THE LONG TERM FORECAST FOR THE TIME BEING AND WENT WITH A GENERAL RAIN...SNOW OR MIX OF THE TWO AS PCPN TYPE. && .AVIATION /03Z THURSDAY THROUGH MONDAY/...
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MAINLY VFR ACROSS THE TERMINALS. WEAK TROUGH PASSES THROUGH THE REGION LATE TONIGHT AND INTO THURSDAY MORNING...POSSIBLY TOUCHING OFF SOME LIGHT SNOW SHOWERS AND/OR FLURRIES WITH BRIEF MVFR CONDS AROUND DAYBREAK THURSDAY. HOWEVER...PROBABILITIES ARE TOO LOW TO INCLUDE THESE LOWER CONDS IN THE TAFS. PRES GRADIENT TIGHTENS OVERNIGHT WITH WINDS/GUSTS INCREASING BETWEEN 06Z AND 12Z...AND STRENGTHEN FURTHER BETWEEN 12Z AND 18Z. .OUTLOOK FOR 00Z THURSDAY THROUGH MONDAY... .THURSDAY NIGHT...VFR. DIMINISHING NW WINDS. .FRIDAY...VFR. .SATURDAY...SUB-VFR POSSIBLE IN BRIEF -SHSN. NW WINDS AROUND 20 KT WITH GUSTS UP TO 30 KT. .SUNDAY-MONDAY...VFR.
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&& .MARINE... A GALE WARNING IS UP FOR THE OCEAN WATERS WITH A SCA ELSEWHERE FOR STRENGTHENING W/NW WINDS TONIGHT INTO THU NIGHT. LOW PRESSURE EAST OF NEW ENGLAND THIS EVE WILL TRACK NE ACROSS THE CANADIAN MARITIMES THROUGH THU NIGHT...WHILE HIGH PRESSURE BUILDS EAST FROM THE MIDWEST. THIS WILL PRODUCE A STRONG GRADIENT WIND. IN ADDITION...COLD AIR ACROSS THE RELATIVELY WARM WATERS WILL ALLOW MIXING OF GALE FORCE GUSTS DOWN TO THE OCEAN SFC. LINGERING SCA CONDS ARE POSSIBLE FRI MORNING ON THE OCEAN WATERS. WINDS AND SEAS OTHERWISE SUBSIDE FOR A BRIEF PERIOD OF SUB-SCA CONDS. WINDS AND SEAS THEN PICK UP AGAIN FRIDAY NIGHT AHEAD OF A COLD FRONT WHICH IS EXPECTED TO PASS THROUGH LATE AT NIGHT INTO SATURDAY MORNING. AFTER ITS PASSAGE...STRONG COLD AIR ADVECTION AND A TIGHT PRESSURE GRADIENT ARE EXPECTED TO BRING GALE FORCE WINDS TO MOST IF NOT ALL WATERS. GALES COULD LAST INTO SATURDAY EVENING FOR THE OCEAN AND EASTERN WATERS...OTHERWISE...WINDS GRADUALLY DIMINISH THROUGH THE NIGHT INTO SUNDAY. SCA CONDS ALL WATERS ON SUNDAY SHOULD QUIET DOWN AGAIN SUNDAY NIGHT AS STRONG HIGH PRESSURE BUILDS OVERHEAD. THE HIGH SHIFTS OFFSHORE ON MONDAY WITH INCREASING WINDS AND SEAS...BUT PROBABLY REMAINING BELOW SCA CRITERIA AT LEAST DURING THE DAYTIME. && .HYDROLOGY... SCT SNOW SHOWERS LATE TONIGHT THROUGH SAT WILL RESULT LIQUID EQUIVALENTS OF LESS THAN A TENTH OF AN INCH. A LOW PRESSURE SYSTEM IMPACTING THE AREA FROM MON NIGHT THROUGH TUES NIGHT COULD BRING A LIQUID EQUIVALENT PCPN AMOUNT OF AN INCH OR GREATER. PRIMARY PCPN TYPE IS UNCERTAIN...SO WILL NEED TO MONITOR THIS SYSTEM FOR POTENTIAL ADVERSE HYDROLOGIC IMPACTS. && .CLIMATE... WITH THE EXTREMELY COLD AIR MASS FORECAST SATURDAY INTO SUNDAY...RECORD MINIMUMS AND RECORD LOW MAXIMUMS MAY BE REACHED. HERE ARE THE RECORDS AND FORECASTS... STATION......RECORD/FCST MINIMUM...RECORD LOW MAXIMUM/FCST HIGH FOR 2/14 FOR 2/14 NYC...........2 (1916) / 1.............17 (1979) / 19 LGA...........1 (1979) / 2.............15 (1979) / 19 JFK...........4 (1979) / 2.............17 (1979) / 19 ISP...........7 (2015) / 1.............26 (1987) / 18 EWR...........0 (1979) / 0.............15 (1979) / 19 BDR...........3 (2015*) / 0.............18 (1979) / 17 *IN 1979 AS WELL && .OKX WATCHES/WARNINGS/ADVISORIES... CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 AM THURSDAY TO 6 AM EST FRIDAY FOR ANZ330-335-338-340-345. SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ350-353- 355. GALE WARNING FROM 6 AM THURSDAY TO 1 AM EST FRIDAY FOR ANZ350- 353-355. && $$ SYNOPSIS...JC/DW NEAR TERM...DW SHORT TERM...DW LONG TERM...JC AVIATION... MARINE...JC/DW HYDROLOGY...JC/DW CLIMATE...

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