Re: Local NWS say 3 coastal system from today-Monday
Posted by Fred on 10/15/2009, 7:55 am

Not going to a pretty weekend.But im not complaining!




000
FXUS61 KOKX 150743
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
343 AM EDT THU OCT 15 2009

.SYNOPSIS...
-- Changed Discussion --
CANADIAN HIGH PRESSURE BUILDS INTO SOUTHEASTERN CANADA THROUGH THE
WEEKEND. A SERIES OF COASTAL LOWS WILL TRACK SOUTH OF LONG ISLAND.
THE FIRST WILL PASS BY TONIGHT AND FRIDAY...THE SECOND LATE SATURDAY
THROUGH SUNDAY MORNING...AND THE THIRD SUNDAY NIGHT AND MONDAY
MORNING. HIGH PRESSURE THEN BUILDS IN DURING THE FIRST PART OF THE
NEW WORK WEEK.
-- End Changed Discussion --


&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
-- Changed Discussion --
MODELS IN GENERAL AGREEMENT WITH REGARD TO THIS COMPLEX AND HIGHLY
ANOMALOUS STORM SYSTEM TODAY. UPPER TROUGH AXIS TO THE WEST...WITH
EMBEDDED SHORTWAVES MOVING AROUND THE BASE OF THIS DEEPENING TROUGH.
AT THE SFC...LOW PRESSURE DEVELOPS AND MOVES NORTHEAST...JUST OFF
THE MID ATLANTIC COAST TODAY. WITH SFC HIGH PRESSURE TO THE
NORTH...A TIGHTENING PRESSURE GRADIENT CAN BE EXPECTED AS NORTHEAST
WINDS INCREASE THROUGH THE DAY. RAIN MOVES IN FROM THE WEST WITH
INCREASING ISENTROPIC LIFT...ALONG WITH MID AND UPPER LEVEL LIFT IN
PLACE.

FOR NORTHWEST PORTIONS OF THE AREA...MAINLY ORANGE COUNTY...PRECIP
TYPE A CHALLENGE. AFTER LOOKING AT PARTIAL THICKNESSES...AND MODEL
FORECAST PROFILES ALONG WITH EXPECTED BOUNDARY LAYER TEMPS...DO
BELIEVE SNOW WILL AT LEAST MIX WITH RAIN. MANY HIGHER ELEVATION
LOCATIONS COULD SEE ALL SNOW FOR A TIME...AND I DO BELIEVE WESTERN
HALF OF ORANGE COUNTY COULD OBSERVE AN INCH OR TWO OF WET SNOW.
HIGHER ELEVATIONS COULD SEE MORE (2 TO 4 IN??) BUT NOT ENOUGH
CONFIDENCE AND LACK OF WIDESPREAD COVERAGE TO ISSUE ANY WINTER WX
ADVISORIES AT THIS TIME. IF LATER TRENDS SUPPORT WIDESPREAD SNOW
ACROSS THE COUNTY...AN ADVISORY MAY BE NEEDED.

FOLLOWED A LAV/MET/MAV BLEND FOR TEMPS...WITH LITTLE CHANGE TO TEMPS
EXPECTED. IN FACT...ANY HEAVIER PRECIP ASSOCIATED WITH
FRONTOGENESIS/DEVELOPING BAROCLINIC ZONE WILL LOWER TEMPS SOMEWHAT
THROUGH THE DAY. TEMPS A GOOD 20 TO 25 DEGREES BELOW NORMAL EXPECTED!
-- End Changed Discussion --


&&

.SHORT TERM /6 AM THIS MORNING THROUGH SATURDAY/...
-- Changed Discussion --
TROUGH AMPLIFIES...AND SFC LOW MOVES NORTHEAST...JUST OUTSIDE THE
BENCHMARK. RAIN...RAIN/SNOW MIX ACROSS THE INTERIOR CONTINUES...THEN
LIGHTENS A BIT FRIDAY AS THAT FIRST LOW PULLS AWAY. NAM/GFS/EC SIMILAR
INTO SATURDAY WITH SECONDARY LOW...BUT INTENSITY AND
PLACEMENT...CLOSER TO THE COAST SATURDAY. THIS IS BEGINNING TO
LOOK LIKE THE MOST LIKELY SCENARIO AS COMPARED TO PROGRESSIVE INVERTED
TROUGH SCENARIO. CHC RAIN/RAIN AND SNOW INTERIOR FRIDAY NIGHT
INTO SATURDAY...THEN LIKELY TO CAT POPS WARRANTED ONCE AGAIN SAT.
OVERALL RAINFALL OF AN INCH TO THE NORTH...AND 2 INCHES TO THE
SOUTH QUITE POSSIBLE.

OVERALL...A PROLONGED STRETCH OF WET WEATHER EXPECTED.

MOS BLEND USED THIS TIME PERIOD...20 TO 25 DEGREES BELOW NORMAL.
-- End Changed Discussion --


&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
-- Changed Discussion --
THE GLOBAL MODEL ENSEMBLE CONTINUES TO POINT TO THE FORMATION OF
A CUTOFF LOW ALONG THE MID ATLANTIC COAST SUNDAY INTO MONDAY. THE
ECMWF AND GFS QUITE CLOSE THIS RUN. GGEM MORE PROGRESSIVE THAN
GFS/EC AS THEY FORECAST SOUTHERN LOW MOVES ALONG FRONTAL BOUNDARY
AND EVENTUALLY BECOMES PRIMARY LOW SUNDAY NIGHT INTO MONDAY.
HOWEVER...A DRYING TREND IS EXPECTED BY ALL MODELS. PRIOR TO THAT
THOUGH...RAIN WILL CONTINUE THROUGH THE SECOND HALF OF THE WEEKEND
WITH A PERSISTENT NE FLOW. POTENTIAL FOR COASTAL FLOODING WILL
CONTINUE DURING THIS TIME.

MERIDIONAL UPPER FLOW FLATTENS TUE-WED AS PAC JET ENERGY RACES
EASTWARD. HI PRES BUILDS ACROSS THE AREA TUE INTO WED.

UNSEASONABLY COOL CONDITIONS TO START THE PERIOD WITH A NE FLOW AND
RAIN. A RETURN TO MORE SEASONABLE CONDITIONS TUE AND WED.
-- End Changed Discussion --


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A Noreaster for the Weekend? - JAC, 10/13/2009, 7:30 am
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