Area Forecast Discussion
Issued by NWS Upton, NY

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KOKX 290909 AFDOKX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 409 AM EST MON DEC 29 2014 .SYNOPSIS...
-- Changed Discussion --
HIGH PRESSURE SLOWLY BUILDS IN THROUGH MIDWEEK...THEN SLIDES SOUTH THROUGH FRIDAY. A LOW PRESSURE SYSTEM APPROACHES NEXT WEEKEND.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
A VERY BROAD UPPER TROUGH ENCOMPASSES MUCH OF CANADA AND EXTENDS INTO THE UNITED STATES. ALOFT A SOUTHWEST FLOW WILL PREVAIL THROUGH TODAY WHILE AT THE SURFACE A STRONG AND COLD HIGH BUILDS FROM WESTERN CANADA AND INTO THE EASTERN STATES...WITH A NORTHWEST FLOW. RATHER STRONG COLD ADVECTION CONTINUES BEHIND A COLD FRONT THAT MOVED THROUGH SUNDAY EVENING. LEANED TOWARD THE COLDER ECMWF GUIDANCE FOR HIGHS AND EVEN UNDERCUT HIGHS INLAND A DEGREE OR TWO.
-- End Changed Discussion --
&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/...
-- Changed Discussion --
A NORTHWEST FLOW CONTINUES TONIGHT THROUGH TUESDAY WITH COLD ADVECTION ALSO CONTINUING. WHILE THE BROAD UPPER TROUGH REMAINS IN PLACE WITH SEVERAL SHORTWAVES ROTATING THROUGH. ONE OF THE WAVES MOVES OUT OF THE CENTRAL PLAINS AND TO SOUTH OF THE DELMARVA TUESDAY. THE ASSOCIATED SURFACE LOW WILL NOW PASS WELL SOUTH OF THE REGION AS THE COLD HIGH DOMINATES. BY TONIGHT TEMPERATURES WILL FALL TO BELOW SEASONAL NORMALS AND REMAIN BELOW INTO THE MIDWEEK. WITH THE COLD TREND REMAINING AGAIN USED THE COLDER ECMWF GUIDANCE.
-- End Changed Discussion --
&& .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
-- Changed Discussion --
OVERALL...QUASI-ZONAL MID TO UPPER LEVEL FLOW THROUGH FRIDAY WITH A RIDGING TREND FOR NEXT WEEKEND. THE MAIN UPPER LEVEL JET WILL BE ALIGNED IN A SIMILAR FASHION AND MOVING SLIGHTLY SOUTH OF THE REGION FOR MIDWEEK BEFORE TRENDING BACK NORTH OF THE AREA FOR THE WEEKEND. AT THE SURFACE...VERY STRONG HIGH PRESSURE OF AT LEAST 1050MB BUILDS INTO THE NORTHWEST PART OF THE COUNTRY AND THIS SINKS SOUTHEAST THROUGH MIDWEEK. THIS WILL BE A SOURCE FOR VERY COLD AIR AND PERIODIC SHORTWAVES WILL MOVE ACROSS THE LOCAL REGION TO HELP WITH ADVECTING THE COLDER AIR MASS INTO THE REGION. THE LOW LEVEL ENVIRONMENT WILL ALSO BECOME VERY DRY AS DIAGNOSED BY FORECAST LAYER PRECIPITABLE WATERS AROUND A TENTH OF AN INCH TUESDAY THROUGH THURSDAY. THIS WILL BE ON AN INCREASING TREND TOWARDS THE WEEKEND BUT AGAIN THERE IS UNCERTAINTY WITH THE FORECAST FOR DAY 7 THROUGH DAY 8 TIME FRAME. THIS UNCERTAINTY IS CONVEYED BY NEARLY A 90 DEGREE PHASE SHIFT BETWEEN CONSECUTIVE RUNS OF THE ECMWF WITH REGARDS TO UPPER LEVEL HEIGHT CONTOUR ORIENTATION. HOWEVER...DID INCREASE POPS A LITTLE WITH AGREEMENT ON PRECIP BETWEEN DGEX...GFS...AS WELL AS SOME GFS ENSEMBLE MEMBERS. JUST A MATTER OF PRECIP TYPE. THIS FORECAST HAS A MIX OF RAIN AND SNOW...SNOW PROBABLY AT ONSET DUE TO WET BULB COOLING AND THEN CHANGING OVER TO RAIN WITH MORE SOUTHERLY FLOW FOR NEXT WEEKEND. HOWEVER...THE CONFIDENCE IS VERY LOW FOR DAY 7 AND DAY 8 TIME FRAME...SO SUBSEQUENT FORECASTS COULD VARY WITH TIMING...PLACEMENT...AS WELL AS PRECIP TYPES. NEAR NORMAL TEMPERATURES RETURN BY FRIDAY AND POSSIBLY ABOVE NORMAL FOR THE WEEKEND. AGAIN...LOWER CONFIDENCE WITH TEMPERATURES NEXT WEEKEND DUE TO AFOREMENTIONED UNCERTAINTY. DRY WEATHER IN THE LONG TERM UNTIL NEXT WEEKEND WITH THE NEXT APPROACHING LOW PRESSURE SYSTEM.
-- End Changed Discussion --
&& .AVIATION /09Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
MARGINAL WINDS AND SEAS EARLY THIS MORNING SHOULD SUBSIDE THROUGH DAYBREAK AS WINDS ALOFT WEAKEN. SUB SCA CONDS TODAY INTO MON NIGHT WITH HIGH PRESSURE NOSING INTO THE REGION. A LOW PROBABILITY OF MARGINAL SCA GUSTS TUE/WED ON OCEAN WATERS WITH GOOD MIXING IN CAA AND AS LOW PRESSURE/S TRACKS WELL SOUTH OF THE REGION. SCA CONDS LIKELY WED NIGHT THRU FRI WITH GOOD MIXING AND A TIGHT W/WSW GRADIENT BETWEEN HIGH PRESSURE TO THE SOUTH AND LOW PRESSURE TO THE NW. LOW PROBABILITY FOR GALE GUSTS ON THE OCEAN WATERS LATE WED NIGHT INTO THU NIGHT. SEAS ON OCEAN WATERS EAST OF FIRE INLET COULD BUILD TO 6 TO 9 FT...AND EVEN 4 TO 6 FT ON THE CENTRAL AND EASTERN LI SOUND THU/THU NIGHT.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
MARGINAL WINDS AND SEAS EARLY THIS MORNING SHOULD SUBSIDE THROUGH DAYBREAK AS WINDS ALOFT WEAKEN. SUB SCA CONDS TODAY INTO MON NIGHT WITH HIGH PRESSURE NOSING INTO THE REGION. A LOW PROBABILITY OF MARGINAL SCA GUSTS TUE/WED ON OCEAN WATERS WITH GOOD MIXING IN CAA AND AS LOW PRESSURE/S TRACKS WELL SOUTH OF THE REGION. SCA CONDS LIKELY WED NIGHT THRU FRI WITH GOOD MIXING AND A TIGHT W/WSW GRADIENT BETWEEN HIGH PRESSURE TO THE SOUTH AND LOW PRESSURE TO THE NW. LOW PROBABILITY FOR GALE GUSTS ON THE OCEAN WATERS LATE WED NIGHT INTO THU NIGHT. SEAS ON OCEAN WATERS EAST OF FIRE INLET COULD BUILD TO 6 TO 9 FT...AND EVEN 4 TO 6 FT ON THE CENTRAL AND EASTERN LI SOUND THU/THU NIGHT.
-- End Changed Discussion --
&& .HYDROLOGY... NO PRECIPITATION IS EXPECTED THROUGH FRIDAY. WIDESPREAD PRECIP POSSIBLE FOR NEXT WEEKEND...BUT IT IS TOO EARLY TO TELL IF IT WILL BE SIGNIFICANT. && .OKX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
CT...NONE. NY...NONE. NJ...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 8 AM EST THIS MORNING FOR ANZ350.
-- End Changed Discussion --
&& $$ SYNOPSIS...MET NEAR TERM...MET SHORT TERM...MET LONG TERM...JM/MET AVIATION...NV MARINE...NV HYDROLOGY...MET

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.