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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 030256
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
956 PM EST MON MAR 2 2015

.SYNOPSIS...
A HIGH PRESSURE AREA WILL BUILD INTO THE REGION OVERNIGHT FROM THE
GREAT LAKES WITH SKIES BECOMING CLEAR. THE HIGH PRESSURE AREA WILL
BE SHORT LIVED AS A STORM SYSTEM MOVES IN FROM THE WEST TUESDAY
NIGHT AND WEDNESDAY. WIDESPREAD SNOW WILL DEVELOP LATE TUESDAY AND
END AS A LITTLE BIT OF MIX OR RAIN SHOWERS WEDNESDAY MORNING. IT
WILL BE MILD WEDNESDAY, BUT COLDER AIR RETURNS WEDNESDAY NIGHT.
HIGH PRESSURE WILL THEN REMAIN IN CONTROL UNTIL THE END OF THE
WEEK.

&&

.NEAR TERM /UNTIL 7 AM TUESDAY MORNING/...
AS OF 955 PM EST MONDAY...SURFACE OBSERVATIONS AND COMPOSITE
RADAR LOOP SHOWING SNOW SHOWERS EARLIER THIS EVENING HAVE COME TO
AN END ACROSS THE REGION WITH SKIES BECOMING CLEAR ACROSS NORTHERN
NEW YORK AND THE CHAMPLAIN VALLEY AT THIS TIME. EXPECTING CLEAR
SKIES OVERNIGHT AS THE RIDGE OF HIGH PRESSURE BUILDS EAST FROM THE
GREAT LAKES OVERNIGHT.

&&

.SHORT TERM /7 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
AS OF 340 PM EST MONDAY...FAIRLY DECENT MODEL AGREEMENT, THOUGH
SOME "DEVIL IN THE DETAILS" REGARDING THERMAL STRUCTURE ALOFT
TUESDAY NIGHT WHICH DOES LEAD TO PRECIPITATION-TYPE ISSUES. LET`S
JUST DISCUSS EACH 12-HOUR BLOCK OF TIME...

TUESDAY: HIGH PRESSURE QUICKLY MOVES OFF TO THE EAST, SO WE START
CLEAR BUT CLOUD OVER IN THE AFTERNOON. 925MB TEMPERATURES IN THE
-12 TO -17C RANGE, WHICH WOULD SUPPORT HIGHS INTO THE MID 20S IN
THE LOWER ELEVATIONS.  FAIRLY ROBUST UPPER TROUGH AND ASSOCIATED
SURFACE LOW WILL BE MOVING INTO THE GREAT LAKES REGION BY
AFTERNOON. CONSIDERABLE WARM AIR ADVECTION, SO BY LATE AFTERNOON
WE SHOULD SEE LIGHT SNOW BREAK OUT, ESPECIALLY FROM THE CHAMPLAIN
VALLEY WESTWARD.

TUESDAY NIGHT: VERY STRONG WARM AIR ADVECTION ONGOING. 850MB WINDS
WILL INCREASE TO 45-55KTS OUT OF THE SOUTH/SOUTHWEST. THUS IT
SHOULD GET FAIRLY BREEZY, IF NOT WINDY, IN THE CHAMPLAIN VALLEY.
THINK WIND GUSTS TO 35 MPH ARE LIKELY. THE STRONG LOW/MID LEVEL
JET WILL BRING WARMER AIR ALOFT, WHICH RESULTS IN A STRONG
ISENTROPIC LIFT. SHOULD SEE A BURST OF MODERATE SNOW IN THE 8PM-
2AM TIMEFRAME PRETTY MUCH AREA WIDE. AFTER THAT TIME, TEMPERATURES
IN THE 800-925MB LEVEL START TO SNEAK ABOVE 0C. THAT MEANS THE
POTENTIAL FOR CHANGE OVER TO DIFFERENT PRECIP-TYPES. GOOD NEWS IS
THAT AS TYPICAL WITH WARM AIR ADVECTION PRECIPITATION EVENTS, MOST
OF THE PRECIPITATION IS OVER WITH PRIOR TO THE MIXING. MODELS ALSO
TYPICALLY SHOW US GETTING MORE PRECIPITATION THAN REALITY DURING THESE
WARM AIR ADVECTION SYSTEMS, SO I ENDED UP TAKING A MODEL BLEND AND
THEN CUTTING BACK A LITTLE. THINK IN GENERAL 0.2 TO 0.3" OF
"LIQUID", HOWEVER THE STRONG WINDS WILL RESULT IN SIGNIFICANT
SHADOWING/DRYING IN THE CHAMPLAIN VALLEY, SO ONLY ABOUT 0.1" OR SO
THERE. TRICKY PART IS TRYING TO ESTIMATE THE SNOW-LIQUID RATIO.
BEST GUESS IS WE WILL BE SOMEWHERE IN THE 10-13:1 RANGE. THIS
GIVES A GENERAL 2-4" OF SNOW, PRIOR TO ANY MIXING HAPPENING. FOR
THE MIXING POTENTIAL, NOTED THE NAM, WHICH IS USUALLY A COLDER
MODEL, WAS WARMEST AND BROUGHT THE MIX ALL THE WAY UP TO NORTHERN
VT. GFS WAS COLDEST AND KEPT EVERYTHING TO THE SOUTH OF VERMONT.
THE EURO AND THE LOCAL 12KM WRF WERE IN-BETWEEN. ENDED UP USING
THE 12KM WRF FOR A LITTLE FINER RESOLUTION. BOTTOM LINE, ANY MIX
SHOULD BE CONFINED TO SOUTH-CENTRAL VERMONT AND THE ST LAWRENCE
VALLEY.

AT THIS POINT WILL NOT ISSUE ANY WINTER WEATHER ADVISORIES. WE`LL
SEE IF LATER MODEL RUNS HAVE A DIFFERENT TREND. A LITTLE NORTHWARD
JOG IN THE MODELS WOULD MEAN A MUCH WETTER (AND LIKELY WARMER)
SITUATION.

WEDNESDAY: LIGHT PRECIPITATION IN THE MORNING SHOULD TAPER OFF AND
END AS LIGHT RAIN SHOWERS FOR MOST EVERYONE. YEP, STILL LOOKING
FOR A WONDERFULLY WARM DAY -- WELL, IF YOU CAN CALL 40S WARM.
STUCK WITH A GUIDANCE MIX THAT HAS BURLINGTON REACHING THE LOWER
40S, BUT NOTED THAT SOME GUIDANCE INDICATED MID TO EVEN UPPER 40S.
IT WILL ALL DEPEND ON HOW SOON THE COLDER AIR STARTS TO MAKE IT`S
WAY IN. GIVEN WINDS TURNING WESTERLY DURING THE DAY (EG:
DOWNSLOPING), AND A DRY SLOT LIKELY GIVING SOME BREAKS IN THE
CLOUDS, I`D GIVE UPPER 40S ABOUT A 40% CHANCE OF HAPPENING. MAYBE
THAT IS JUST ME WISH-CASTING ;)

WEDNESDAY NIGHT: THE WARMTH IS SHORT LIVED. WINDS TURN NORTHWEST
AND COLD-AIR ADVECTION CONTINUES. SHOULD DROP INTO THE TEENS
ACROSS VERMONT, WITH LOWS CLOSER TO ZERO OUT IN THE ST LAWRENCE
VALLEY. STILL SOME WIND AND SOME CLOUDS ABOUT AND PERHAPS A
MOUNTAIN FLURRY. STUCK TO A GUIDANCE BLEND FOR TEMPERATURES.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 315 PM EST MONDAY... GIVEN THE LACK OF ACTIVE WEATHER
EXPECTED IN THE EXTENDED I`LL FORGO DAILY DESCRIPTIONS IN FAVOR OF
A BROAD GENERAL IDEA OF THE PATTERN FROM THURSDAY ONWARD. A BROAD
NORTHERN UPPER LEVEL TROUGH WILL COMBINE WITH A BROAD DOME OF HIGH
PRESSURE TO SUPPRESS ANY SYNOPTIC FORCING OF PRECIP WITH THE LONE
EXCEPTION BEING A WEAK SHORTWAVE DISTURBANCE ON SATURDAY. THAT
WILL BRING A CHANCE OF SNOW SHOWERS ESPECIALLY IN THE HIGHER
TERRAIN OF THE ADIRONDACKS AND GREENS.

CONCERNING TEMPERATURES... WE WILL SEE A GENERAL WARMING PATTERN
WITH THURSDAY AND FRIDAY BEING THE COLDEST TWO DAYS WITH HIGHS IN
THE LOW TO MID 20S WARMING TO MORE SEASONABLE TEMPS AROUND FREEZING
TO THE MID 30S OVER THE WEEKEND. OVERNIGHT LOWS WILL BE QUITE CHILLY
ON THURSDAY AND FRIDAY NIGHT AS MOSTLY CLEAR SKIES WILL ALLOW FOR
GOOD RADIATIONAL COOLING BRING LOWS IN THE LOW SINGLE DIGITS ABOVE
AND BELOW ZERO. INTO THE WEEKEND WITH THE WARMING TREND CONTINUING
OVERNIGHT LOWS SHOULD WARM INTO THE MID TEENS TO NEAR 20 INSIDE THE
CHAMPLAIN VALLEY.

WINDS DURING THE PERIOD WILL BE GENERALLY LIGHT TO MODERATE WEST TO
SOUTHWESTERLY UNDER THE UPPER LEVEL TROUGH AXIS WITH MOSTLY CLEAR
SKIES EXCEPT FOR A SHORT PERIOD OF INCREASING CLOUDS NEAR THE
INTERNATIONAL BORDER EARLY SATURDAY MORNING.

&&

.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
THROUGH 00Z WEDNESDAY...PREDOMINANTLY VFR EXPECTED FOR MOST TAF
SITES THROUGH THE PERIOD. SCATTERED SNOW SHOWERS AND GUSTY
WEST/NORTHWEST WINDS WILL END DURING THE EVENING HOURS WITH ANY
REDUCTIONS IN CEILINGS/VISIBILITIES GONE BY 02Z. OTHERWISE
CONDITIONS IMPROVE TO VFR...SKIES BECOME CLEAR...AND WINDS
GRADUALLY SLACKEN OVERNIGHT. WINDS WILL TURN SOUTHERLY ON TUESDAY
AND BEGIN TO GUST TUESDAY AFTERNOON...WITH 15-20 KNOT GUSTS
LIKELY...ESPECIALLY BTV/PBG/SLK. MID/HIGH DECK OF CLOUDS ALSO
INCREASES AFTER 15-17Z...WITH LOWER DECK ALONG WITH A PERIOD OF
SNOW MOVING INTO NORTHERN NY AND MSS/SLK AFTER 22Z. CONDIITONS
SHOULD REMAIN DRY AT OTHER TAF SITES THROUGH ABOUT 00Z WEDNESDAY.

OUTLOOK 00Z WEDNESDAY THROUGH SATURDAY...
00Z WEDNESDAY THROUGH 18Z WEDNESDAY... MVFR/IFR IN PERIODS OF
LIGHT SNOW LIFTING TO VFR WEDNESDAY AFTERNOON AS PRECIPITATION
MIXES WITH RAIN SHOWERS AND DISSIPATES.

18Z WEDNESDAY THROUGH 00Z FRIDAY...MAINLY VFR ALTHOUGH SOME
PERIODS OF MVFR/IFR ARE POSSIBLE IN LIGHT SNOW SHOWERS AS SYSTEM
SLIDES TO THE SOUTH.

00Z FRIDAY THROUGH 12Z SATURDAY...VFR UNDER RIDGE OF HIGH
PRESSURE.

12Z SATURDAY ONWARD...MVFR/IFR POSSIBLE IN SNOW SHOWERS WITH
FRONTAL SYSTEM.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...NONE.
NY...NONE.

&&

$$
SYNOPSIS...NASH
NEAR TERM...WGH
SHORT TERM...NASH
LONG TERM...DEAL
AVIATION...MUCCILLI