Snow ??

46er

Piney
Mar 24, 2004
8,837
2,143
Coastal NJ
It all depends.....

iws0_430.jpg
 

Boyd

Administrator
Staff member
Site Administrator
Jul 31, 2004
9,547
2,806
Ben's Branch, Stephen Creek
Actually yesterday morning was colder than today at my place. At 6:00AM it was 31 yesterday with some heavy frost on the car windows. Light frost on the windows today and 33.

Kind of a crazy forecast for the next few days... temp will rise through the 50's tonight, then low 60's tomorrow, back into the 30's tomorrow night. Weather Underground is forecasting 40$ chance of snow with lows in the 20's on Saturday night.
 

imkms

Explorer
Feb 18, 2008
587
224
SJ and SW FL
Snow predictions

I like to go to the NWS site and read the "Forecast Discussion". This is written in very technical terms, which I only partially understand, but it is a listing of just the facts without the hype or exaggeration usually heard from the radio or TV weather forecasters. The discussion is updated several times a day and I find it to be very accurate, if you can understand it! Pasted below is some of the current wording for Saturdays weather as of 1224 PM EST FRI DEC 4 2009

.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
THIS TIME FRAME WILL BE TRENDING RATHER INTERESTING. AS AN
UPPER-LEVEL TROUGH SWINGS THROUGH THE GREAT LAKES TO THE GULF COAST
REGION TONIGHT, LARGE SCALE LIFT WILL BECOME ENHANCED ALONG AND
NORTH OF A BAROCLINIC ZONE POSITIONED FROM THE GULF MEXICO TO OFF
THE SOUTHEASTERN UNITED STATES COAST. THIS HELPS TO ORGANIZE A
SURFACE LOW AS THE THERMAL GRADIENT STRENGTHENS SOME AND THE RIGHT
ENTRANCE REGION OF A 140-KNOT 250 MB JET COMES INTO PLAY. IN
ADDITION, THE INCOMING SHORT WAVE TROUGH IN THE SOUTHERN STATES
TENDS TO SHARPEN UP SOME MORE. THE COMPUTER MODEL GUIDANCE HAS BEEN
SHOWING THIS FEATURE FOR SOME TIME NOW, HOWEVER THE TRACK OF THE
SURFACE LOW AND HOW MUCH LIFT GETS PULLED NORTHWESTWARD AS THE
MIDLEVEL FEATURE EJECTS NORTHEASTWARD HAS BEEN IN QUESTION.

PER HPC, THE NAM/WRF IS ON THE MORE AMPLIFIED SIDE OF THE MODEL
GUIDANCE SPREAD STARTING LATE FRIDAY WITH PORTIONS OF THE MIDLEVEL
SHORT WAVE FORECAST TO CROSS THE EAST COAST SATURDAY NIGHT. AS A
RESULT, THE WESTERN ATLANTIC SURFACE LOW IS ONE OF THE FARTHER
WESTWARD TRACKS AMONG LATEST GUIDANCE. THE NAM/WRF HAS TRENDED
SLIGHTLY FASTER WITH THE MIDLEVEL ENERGY OVER THE PAST DAY. THE GFS
LEANS TOWARD THE QUICKER EDGE OF THE MODEL GUIDANCE ENVELOPE FROM
LATE FRIDAY ONWARD, WITH A WESTERN ATLANTIC SURFACE LOW EVOLUTION
THAT LEANS TOWARD THE FAST EDGE OF THE GUIDANCE. THE GFS HAS TRENDED
NOTICEABLY FASTER IN THE PAST DAY AS WELL SO ITS FASTER TIMING
CANNOT BE COMPLETELY DISCOUNTED. HOWEVER, THE 00Z ECMWF REMAINS
SLOWER THAN THE GFS, WITH ITS SOLUTION ALOFT COMPARING WELL TO THE
UKMET/CANADIAN GLOBAL, WHICH ARE SLIGHTLY STRONGER WITH THE TROUGH
THAN THE GFS. HPC MENTIONED THAT THE WESTWARD ADJUSTMENT OF THE 00Z
ECMWF FROM ITS PREVIOUS RUNS ALSO BRINGS IT TO THE MIDDLE OF THE
SPREAD BETWEEN THE NAM/WRF AND GFS. THE ECMWF MAY STILL BE A LITTLE
SLOW TO DEEPEN THE SURFACE LOW BASED ON REMAINING OPERATIONAL
GUIDANCE. SOME OF THE MODELS HAVE ALSO TRENDED A BIT WETTER AS WELL.

WE MAINLY UTILIZED A BLEND OF THE ECMWF AND UKMET FOR THE SATURDAY
AND SATURDAY NIGHT EVENT. BACKING UP A BIT, THE STRONG UPPER-LEVEL
JET IS FORECAST TO BE LIFTING GRADUALLY NORTHWARD TONIGHT AND EVEN
STRENGTHEN SOME MORE. THIS COMBINED WITH GRADUAL MOISTURE ADVECTION
ABOVE THE BOUNDARY LAYER WILL ALLOW FOR AN INCREASE AND THICKENING
OF THE CLOUDS TONIGHT. THESE CLOUDS MAY TEND TO KEEP TEMPERATURES UP
SOME DUE TO LESS CONDUCIVE RADIATIONAL COOLING CONDITIONS. IN
ADDITION, HIGH PRESSURE THAT SHIFTS NORTH OF OUR AREA LOOKS TO
ACTUALLY BECOME REESTABLISHED TO OUR WEST LATE TONIGHT INTO SATURDAY.
THIS WILL ALLOW THE WINDS TO SHIFT TO THE NORTH AND NORTHEAST AND
PERHAPS PICK UP SOME ESPECIALLY LATE TONIGHT. ALL OF THIS MAY TEMPER
THE LOWERING OF THE TEMPERATURES TO SOME EXTENT DESPITE LOWER
SURFACE DEW POINTS. AS THE SURFACE LOW ORGANIZES AND MOVES OFF THE
EAST COAST DURING SATURDAY, LARGE SCALE LIFT WILL SPREAD NORTHWARD.
THERE ARE SOME DIFFERENCES AMONG THE MODELS ON HOW MUCH
PRECIPITATION GETS FARTHER NORTH AND WEST, AND IT WILL BE
INTERESTING TO SEE HOW MUCH THE LOW-LEVEL DRYING HOLDS BACK THE
ADVANCING PRECIPITATION SHIELD. SOME OF THE FORECAST SOUNDINGS AND
EVEN THE GFS QPF FIELDS HINT AT DRY LOW-LEVEL AIR HOLDING FIRM FOR
AWHILE. DESPITE THIS, A DECENT AMOUNT OF MOISTURE TRANSPORT SHOULD
OCCUR NORTHWARD WITH TIME AS THE FLOW IS SOUTHWEST ALOFT AND EVEN
STRENGTHENS. FORECAST SOUNDINGS INDICATE THAT THE WESTERN ZONES ARE
COLD ENOUGH FOR MAINLY SNOW WITH RAIN TO START FARTHER TO THE EAST.
WITH A MILD OCEAN JUST TO OUR EAST, THE COASTAL AREAS WILL HAVE RAIN
BUT COULD MIX WITH OR END AS SOME SNOW. INTERESTING TO NOTE THAT
SOME GUIDANCE, LIKE THE NAM MOS, SHOWS LOWER SURFACE DEW POINTS
ESPECIALLY FOR THE INLAND AREAS. THIS MAY HELP TO EVENTUALLY COOL
THE COLUMN FURTHER ESPECIALLY IF THE PRECIPITATION INTENSITY
STRENGTHENS SOME. THERE IS A BAND OF LOW-LEVEL FRONTOGENETIC FORCING
THAT OVERSPREADS THE AREA, THEREFORE THAT COULD KICK UP THE
INTENSITY SOME. MODEL CROSS SECTIONS REVEAL THAT THE OMEGA FIELDS DO
INTERSECT THE SNOW GROWTH AREAS FOR A TIME SATURDAY INTO SATURDAY
NIGHT, HOWEVER THIS DOES NOT LOOK LIKE AN IDEAL SETUP AS THE
FORECAST OMEGA IS ON THE WEAKER SIDE. WE TRIED TO PRESERVE SOME
CONTINUITY WITH OUR PRECIPITATION TYPES, HOWEVER DID TWEAK POPS SOME
AND EVEN TIGHTEN THEM UP A BIT. BASICALLY CHC ACROSS THE WESTERN
AREAS TO LIKELY AND CATEGORICAL AS ONE HEADS EASTWARD. THE POPS
INCREASE FROM SOUTHEAST TO NORTHWEST DURING THE COURSE OF SATURDAY.

BASED ON THE ABOVE AND LOWER CONFIDENCE ON HOW MUCH SNOW ACTUALLY
STICKS, WE WILL PAINT IN A SWATCH OF AROUND AN INCH OF SNOW MOSTLY
CENTERED ALONG INTERSTATE 95. THIS IS CLOSE TO THE LATEST HPC WWD
SNOW GRAPHIC. WE WILL HAVE TO SEE HOW MUCH SNOW CAN ACTUALLY STICK
TO THE GROUND GIVEN THE BOUNDARY LAYER TEMPERATURES. WE WILL
CONTINUE TO HIGHLIGHT THIS EVENT IN THE HAZARDOUS WEATHER OUTLOOK.
STAY TUNED.

THE STORM EJECTS NORTHEASTWARD AND AWAY FROM OUR REGION EARLY
SUNDAY, THEREFORE WE TAPERED THE POPS DOWN FAIRLY QUICKLY SATURDAY
NIGHT WITH DRY CONDITIONS EXPECTED ON SUNDAY AS HIGH PRESSURE
RETURNS. THE SKY MAY TEND TO CLEAR QUICKLY SATURDAY NIGHT INTO
SUNDAY AND TEMPERATURES LOOK TO DROP BELOW FREEZING. WE MAY NEED TO
WATCH OUT FOR DEVELOPING ICY SPOTS DEVELOPING DUE TO THE FALLEN
RAIN/SNOW AND ANY REMAINING WET SURFACES.
 
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