-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 231532
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
1132 AM EDT WED JUL 23 2014

.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION TODAY INTO THIS EVENING ALONG
WITH SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS. A FEW OF THE
STORMS MAY BECOME STRONG TO SEVERE FROM THE ADIRONDACKS EASTWARD
INTO VERMONT...WITH STRONG GUSTY WINDS THE PRIMARY THREAT. BEHIND
THE FRONT DRIER AND MORE PLEASANT WEATHER IS EXPECTED BY THURSDAY
INTO THE FIRST HALF OF THE UPCOMING WEEKEND.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AS OF 1131 AM EDT WEDNESDAY...SHOWERS AND THUNDERSTORMS
DEVELOPING ACROSS NORTHERN NEW YORK AT THIS TIME AND EXTENDING
INTO NORTHWEST VERMONT AT THIS TIME AND JUST NORTH OF THE VERMONT-
QUEBEC BORDER. PREVIOUS FORECAST IN GOOD SHAPE. THE MAIN THREAT
TODAY REMAINS LOCALLY HEAVY RAINFALL AND STRONG GUSTY WINDS.
MASSENA NEW YORK HAD 1.26 INCHES OF RAINFALL FROM 7 AM TO 10 AM
THIS MORNING. THIS STILL REMAINS BELOW FLASH FLOOD GUIDANCE FOR
THERE WHICH IS 2.7 INCHES IN 3 HOURS.

PREVIOUS DISCUSSION FROM 732 AM EDT WEDNESDAY...FORECAST REMAINS
IN GOOD SHAPE WITH ONLY MINOR ADJUSTMENTS TO SKY/T/TD DATASETS TO
NUDGE TOWARD CURRENT OBSERVATIONAL TRENDS AS OF 700 AM. WATCHING
STORMS ALREADY ENTERING OUR SLV COUNTIES WHERE RECENT TOPS TO 45
KFT OBSERVED. WILL CONTINUE TO MONITOR.

PRIOR DISCUSSION FROM 345 AM EDT WEDNESDAY...ACTIVE WEATHER IN
STORE FOR THE EASTERN HALF OF THE FORECAST AREA TODAY INTO THIS
EVENING AS SURFACE COLD FRONT MAKES STEADY PROGRESS THROUGH NY/NEW
ENGLAND. MODELS CONTINUE TO ADVERTISE A DECENT COMBINATION OF PBL
INSTABILITY AND 30-40KT OF DEEP LAYER SHEAR ALONG AND AHEAD OF THE
SFC BOUNDARY SO IDEA OF SCT/NUMEROUS SHOWERS/STORMS...SOME LOCALLY
STRONG TO SVR STILL LOOKS GENERALLY ON TRACK. FLIES IN THE
OINTMENT HOWEVER...SUCH AS LACK OF A DEFINITIVE SHORTWAVE AND
RATHER WEAK MID LEVEL LAPSE RATES SO WIDESPREAD SVR NOT AS LIKELY.
GIVEN TIMING OF FRONTAL ZONE FEEL BEST THREAT OF STRONGER
CONVECTION WILL OCCUR FROM OUR EASTERN NEW YORK COUNTIES INTO
VERMONT...ESP CENTRAL/ERN VT WHERE DECENT SFC HEATING THROUGH
MIDDAY SHOULD PUSH CAPE VALUES INTO THE 1500-2000 J/KG RANGE.
UNIDIRECTIONAL WSW PRE- FRONTAL FLOW SHOULD KEEP CONVECTIVE MODE
MORE LINEAR IN NATURE WITH A SHORT QLCS FEATURE POSSIBLY EVOLVING
ACROSS CENTRAL INTO NERN VT BY EARLY AFTERNOON. WIND TO BE THE
PRMIARY CONCERN GIVEN STEEP LOW LEVEL LAPSE RATES. CAN`T RULE OUT
A FEW INSTANCES OF LARGER HAIL WITH MOST INTENSE CORES AS
WELL...BUT WITH WBZ VALUES QUITE HIGH (ABV 11 KFT) WILL DOWNPLAY
THIS FOR NOW. ALSO SOME DECENT DOWNPOURS AS PWATS SPIKE TO NEAR 2
INCHES IN A NARROW BAND ALONG THE BOUNDARY...BUT FLOODING THREAT
APPEARS LOW GIVEN THE CELLS SHOULD BE MOVING ALONG IN THE DEEP WSW
FLOW. HIGHS A BLEND OF AVAILABLE GUIDANCE...WITH WARMEST VALUES IN
VERMONT (80S) AND SLIGHTLY COOLER ACROSS NRN NY (70S) WITH EARLIER
ARRIVAL OF THE FRONT AND CLOUDS.

BY THIS EVENING THE SFC FRONT CONTINUES TO MAKE STEADY PROGRESS
EASTWARD...CLEARING OUR EASTERN VERMONT COUNTIES BY MID TO LATE
AFTERNOON AS WINDS TREND NORTHWESTERLY IN ALL AREAS. THUS LINGERING
SHOWERS/STORMS EAST SHOULD EXIT BY MIDNIGHT IF NOT A TAD SOONER.
HOWEVER...WILL OPT TO DELAY CLEARING TREND SOMEWHAT AS RECENT
SATELLITE/OBSERVATIONAL TRENDS ACROSS SC CANADA SHOWING PLENTY OF
POST-FRONTAL COLD ADVECTION STRATOCUMULUS NOW OCCURRING. LOWS QUITE
PLEASANT AND GENERALLY IN THE 50S FOR MOST SPOTS.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
AS OF 345 AM EDT WEDNESDAY...REMAINDER OF THE FORECAST THROUGH
FRIDAY TRENDS SLIGHTLY COOLER AND MAINLY DRY AS SURFACE HIGH
PRESSURE BUILDS EASTWARD AND IS BRIDGED ALOFT BY CYCLONIC FLOW
WITHIN MEAN ERN CONUS LONGWAVE UPPER TROUGH. WILL STILL ADVERTISE
JUST AN OUTSIDE SHOT OF A FEW SHOWERS ACROSS THE NRN MTNS BY
FRIDAY AFTERNOON AS A WEAK SECONDARY SFC TROUGH SETTLES SOUTH INTO
THE AREA AND WASHES OUT. HOWEVER COVERAGE SHOULD BE FAIRLY LIMITED
WITH SUCH DRY LOWER AND MID LEVELS AND THE LARGER VALLEYS SHOULD
REMAIN LARGELY DRY. HIGHS DURING THE PERIOD RANGING THROUGH THE
70S TO AROUND 80 WITH OVERNIGHT LOWS ON THURSDAY SEASONABLY COOL
FROM 45 TO 55 ALONG WITH PATCHY FOG.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 329 AM EDT WEDNESDAY...THERE`S A LITTLE BETTER AGREEMENT
TODAY AMONG 00Z/23 GUIDANCE SUITE IN THE EXTENDED PERIOD. WELL
SPECIFIED MID- TROPOSPHERIC REGIME ADVERTISED IN SEVERAL MODEL
CYCLES FEATURES PHASING OF A LARGE NORTHEASTERN NOAM UPPER LOW
WITH A SHORTWAVE TROUGH MOVING ACROSS THE NORTHERN PLAINS/CANADIAN
PRAIRIES SATURDAY NIGHT/SUNDAY. THAT RESULTS IN WESTWARD
RETROGRESSION OF MEAN TROUGHING ALOFT AND MAINTAINS CYCLONIC FLOW
AND UNSETTLED CONDITIONS FOR THE NORTH COUNTRY INTO EARLY NEXT
WEEK. GIVEN A LIKELY SLOW-EVOLVING PATTERN THE 00Z GFS LOOKS TO BE
A BIT TOO FAST IN ITS DEPICTION OF EJECTING SHORTWAVE ENERGY FROM
THE GREAT LAKES TO THE NORTHEAST SUNDAY INTO MONDAY.
THEREFORE...PREFERENCE IS GIVEN TOWARD THE SLOWER 00Z ECMWF IN THE
EXTENDED. SENSIBLE WX HIGHLIGHTS INCLUDE SEVERAL OPPORTUNITIES FOR
SHOWERS/PSBL STORMS - THOUGH NOTHING THAT SEEMS TO BE A WASHOUT ON
ANY PARTICULAR DAY - AND GENERALLY SEASONABLE TEMPS.

I CARRIED A TOKEN SLIGHT CHANCE FOR LEFTOVER DIURNAL SHOWERS
ACROSS NORTHERN TIER/MOUNTAINS EARLY FRIDAY NIGHT BUT TRENDING
DRY LATE FRIDAY NIGHT INTO SATURDAY. SUNDAY INTO TUESDAY LOOK TO
BE UNSETTLED WITH HIGH CHANCE POPS SHOWN AS MEAN UPPER TROUGH
RETROGRADES WESTWARD...LEAVING THE NORTH COUNTRY IN A BROAD
SOUTHWEST FLOW ALOFT. LIMITED INSTABILITY OFFERS POTENTIAL FOR
SOME THUNDERSTORMS EACH DAY...BUT FEEL CHANCES FOR THUNDER WOULD
BE LOWER EACH DAY GOING FORWARD AS SYNOPTIC-SCALE LIFT GETS
PROGRESSIVELY WEAKER. HIGHS GENERALLY IN THE 70S TO LOW 80S WITH
LOWS IN THE 50S TO LOW 60S.

&&

.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 12Z THURSDAY...THOUGH LIKELY VFR MOST OF THE TIME...AN
ACTIVE AVIATION PERIOD ANTICIPATED WITH POTENTIAL FOR
STRONG/LOCALLY SEVERE THUNDERSTORMS AS COLD FRONT MOVES ACROSS THE
REGION. ALREADY SEEING THUNDERSTORMS NEAR MSS EARLY THIS MORNING
AND HAVE INDICATED VCTS WITH TEMPO -TSRA. VCSH WITH TEMPO -TSRA AT
SLK PBG AND BTV 14-16Z BUT HAVE HELD OFF MENTION OF TSRA AT RUT
AND MPV WITH THREAT AT THOSE SITES LIKELY AT/AROUND 18Z. ANY
THUNDERSTORM HAS POTENTIAL FOR BRIEF IFR VISIBILITY IN HEAVY RAIN
WITH STRONGER STORMS PRODUCING LLVL TURBULENCE AND MORE LIMITED
THREAT OF HAIL. SOUTH WINDS 10-12 KTS WITH OCCASIONAL GUSTS TO
20-22 KTS...BUT NOTABLE WIND SHIFT TO NORTHWEST AROUND 10 KTS WITH
FRONTAL PASSAGE. NORTH WINDS LOOK TO DROP OFF SOME WEDNESDAY
EVENING WITH HIGH PRESSURE BUILDING IN...THOUGH INDICATIONS FROM
BUFKIT SOUNDINGS AND CURRENT POST- FRONTAL OBS ACROSS ON/NORTHERN
GREAT LAKES STILL SUGGEST LOWER CEILINGS TO LINGER WELL AFTER
FRONTAL PASSAGE. IF GREATER CLEARING CAN OCCUR...THEN SOME
POTENTIAL FOR IFR VISIBILITY IN FOG 06-12Z FOR MPV AND SLK.

OUTLOOK 12Z THURSDAY THROUGH SUNDAY...

12Z THU - 00Z MON...VFR UNDER HIGH PRESSURE. LATE NIGHT AND EARLY
MORNING IFR OR LOWER VISIBILITY IN FOG/MIST AT MPV AND SLK
POSSIBLE. AN ISOLATED AFTERNOON SHOWER OVER THE HIGHER TERRAIN IS
POSSIBLE FRIDAY.

&&

.MARINE...
AS OF 1131 AM EDT WEDNESDAY...A LAKE THUNDERSTORM ADVISORY IS NOW
IN EFFECT FOR LAKE CHAMPLAIN THROUGH THIS EVENING. COMPOSITE RADAR
LOOP AT THIS TIME SHOWING THUNDERSTORMS ACROSS THE NORTHERN
PORTION OF LAKE CHAMPLAIN MAINLY NORTH OF A PLATTSBURGH-SAINT
ALBANS LINE TO THE CANADIAN BORDER. EXPECTING ADDITIONAL SHOWERS
AND THUNDERSTORMS TO DEVELOP ACROSS THE REMAINDER OF LAKE
CHAMPLAIN THIS AFTERNOON. SOUTH WINDS WILL BE 10 TO 20 KNOTS WITH
WAVES OF 1 TO 2 FEET EXPECTED. THE MAIN THREAT FROM THUNDERSTORMS
TODAY WILL BE LOCALLY GUSTY WINDS AND HEAVY RAINFALL AS WELL AS
LIGHTNING. IF THREATENING WEATHER APPROACHES SEEK SAFE HARBOR
IMMEDIATELY.

&&

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

&&

$$
SYNOPSIS...JMG
NEAR TERM...JMG/WGH
SHORT TERM...JMG
LONG TERM...LOCONTO
AVIATION...LOCONTO
MARINE...WGH