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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KBTV 221123
AFDBTV

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BURLINGTON VT
723 AM EDT WED MAY 22 2013

.SYNOPSIS...
MOSTLY CLOUDY SKIES ARE EXPECTED ACROSS THE NORTH COUNTRY TODAY.
A WARM FRONT LIFTING NORTHEASTWARD ACROSS THE REGION LATE THIS
AFTERNOON AND EVENING WILL BRING THE POTENTIAL FOR ISOLATED TO
SCATTERED SHOWERS AND THUNDERSTORMS. SOME THUNDERSTORMS MAY
PRODUCE SMALL HAIL...GUSTY WINDS...AND LOCALLY HEAVY DOWNPOURS. A
SLOW-MOVING COLD FRONT WILL THEN APPROACH FROM THE EASTERN GREAT
LAKES REGION BRINGING ADDITIONAL WIDESPREAD RAINFALL AND EMBEDDED
THUNDERSTORMS DURING THURSDAY AND THURSDAY NIGHT. WHILE IT WON/T
BE RAINING CONTINUOUSLY...PERIODS OF BRIEFLY HEAVY RAIN ASSOCIATED
WITH THE SHOWERS AND THUNDERSTORMS WILL GENERALLY BRING AN
ADDITIONAL 1 TO 2 INCHES OF RAIN ACROSS THE NORTH COUNTRY THROUGH
THURSDAY NIGHT. SOME MINOR FLOODING WILL BE POSSIBLE...MAINLY
THURSDAY INTO THURSDAY NIGHT WITH THE MOST WIDESPREAD RAINFALL.

&&

.NEAR TERM /UNTIL 8 PM THIS EVENING/...
-- Changed Discussion --
AS OF 722 AM EDT WEDNESDAY...UNSETTLED PATTERN CONTINUES ACROSS THE
NORTH COUNTRY IN VCNTY OF E-W ORIENTED FRONTAL ZONE WHICH REMAINS
DRAPED ACROSS THE REGION. SFC TROUGH AND 850MB TEMP GRADIENT
SUGGESTS SYNOPTIC FRONTAL ZONE IS UP NEAR THE INTL BORDER...BUT
GIVEN THE WIDESPREAD CONVECTION THAT HAS OCCURRED IN SEVERAL WAVES
DURING THE PAST 6-12 HOURS...THE EFFECTIVE FRONTAL POSITION
EXTENDS ACROSS THE SRN TIER OF NY INTO NWRN CT WHERE LARGE
MESOSCALE COLD POOL HAS BEEN ESTABLISHED.

WILL SEE PATCHY FOG ACROSS THE REGION THRU 13Z GIVEN SATURATED
LOW-LEVEL CONDITIONS AND GENERALLY LIGHT WINDS. WEAK SFC LOW
ACROSS NRN NY WILL GENERALLY DISSIPATE THRU THE REMAINDER OF THIS
MORNING. THERE ARE SLIGHT 700-500MB HEIGHT RISES THIS MORNING THRU
EARLY AFTN...AND ABSENCE OF LOW-LEVEL CONVERGENCE SUGGESTS
ADDITIONAL RAINFALL IS UNLIKELY THRU ABOUT 19Z. CLOUDS BUT NO PCPN
THRU MID AFTN...WILL TREND SKY COVER FROM OVC TO BKN BY NOONTIME.
THEREAFTER...THERE IS A SWLY BACKING AND STRENGTHENING OF 850MB
FLOW ACROSS WRN PA INTO CENTRAL NY PER MODEL GUIDANCE. FEEL THAT
REMNANT OUTFLOW BOUNDARY ACROSS CENTRAL NY WILL ENHANCE ISENTROPIC
ASCENT LATE IN THE DAY ACROSS THE ADIRONDACKS AND S-CENTRAL
VT...ALLOWING FOR DEVELOPMENT OF SHOWER AND TSTM ACTIVITY. THE 00Z
NAM SHOWS DEVELOPMENT OF MUCAPE OF 500-1000 J/KG ACROSS ALL BUT
NERN PORTION OF THE FORECAST AREA 21-00Z. RAP SOUNDINGS SHOW A BIT
MORE INSTABILITY...UP TO 1500 J/KG...THOUGH SFC DEWPOINTS MAY BE A
BIT OVERDONE HERE. BASED ON CONSENSUS OF THE MODELS INCLUDING
LOCALLY RUN 4KM WRF...LOOKING FOR DEVELOPMENT OF A FEW STRONG LATE
DAY/EVENING TSTMS AS WELL. SPC CALIBRATED SVR PROBABILITIES AND
DAY 1 OUTLOOK SUPPORT A FEW SEVERE STORMS...AND MENTIONED GUSTY
WINDS AND SMALL HAIL IN THE FORECAST AND HWO FOR LATE
AFTN/EVENING. DEEP LAYER (SFC-6KM) SHEAR EXCEEDS 40 KTS AND IS
SUPPORTIVE OF SOME LONG-LIVED UPDRAFTS. 00Z ALB SOUNDING SHOWED PW
VALUES OF 1.52"...AND NWD ADVECTION OF THIS MOIST AIR MASS WILL
ALSO YIELD LOCALLY HEAVY DOWNPOURS WITH THE CONVECTION LATE THIS
AFTN INTO THIS EVENING. AFTN TEMPS TODAY HIGHLY DEPEND ON SOME
SUNNY BREAKS DURING THE LATE MORNING-MID AFTN PERIOD. ANTICIPATE
SOME INTERVALS OF SUN TODAY...AND WITH 850MB TEMPS OF +14C COULD
WARM QUICKLY DURING THE EARLY AFTN. HIGH TEMPERATURES IN THE
VALLEYS GENERALLY IN THE MID TO UPR 70S...BUT COULD REACH 80F IF
WE GET A BIT MORE SUNSHINE AND INSOLATIONAL HEATING.
-- End Changed Discussion --

&&

.SHORT TERM /8 PM THIS EVENING THROUGH FRIDAY/...
AS OF 418 AM EDT WEDNESDAY...DEEP-LAYER SWLY FLOW AND WARM ADVECTION
CONTINUES OVERNIGHT...WITH BEST ISENTROPIC ASCENT GRADUALLY
SHIFTING NORTH AND EAST. HAVE CARRIED LIKELY POPS FOR WIDESPREAD
SHOWERS AND CONTINUED EMBEDDED TSTMS. SOME DECREASE IN CAPE
OVERNIGHT...SO KEPT ENHANCED WIND/HAIL WORDING JUST THRU THE
EVENING HOURS. LOWS WILL BE ON THE WARM SIDE TONIGHT WITH 60S
DEWPOINTS IN PLACE ALONG WITH CLOUDS AND S-SW WINDS ALL NIGHT. LOW
TEMPS WILL MAINLY BE IN THE UPR 50S TO LOWER 60S.

THURSDAY WILL PRODUCE OUR MOST WIDESPREAD RAINFALL AS COLD FRONT AND
ASSOCIATED POSITIVE TILT 500MB TROUGH BEGINS TO SHIFT SLOWLY SEWD
ACROSS THE FORECAST AREA. MOIST AND MARGINALLY UNSTABLE AIR MASS
WILL SUPPORT SEVERAL BANDS OF SLOW MOVING CONVECTION ALONG/IN
ADVANCE OF THE COLD FRONT. GIVEN THE SETUP...MOST OF THE NWP QPF
LOOKED ON THE LOW SIDE GIVEN EVOLUTION AND MOIST AIR MASS IN
PLACE. TRENDED CLOSER TO HIGHER ECMWF QPF WITH WIDESPREAD 1+"
RAINFALL AMTS ACROSS THE CWA. SOME OF THIS HEAVY RAIN CONTINUES
INTO THURSDAY NIGHT...ESPECIALLY CENTRAL AND ERN VT. CAN/T RULE
OUT LOCALIZED 2" RAINFALL AMTS BEFORE THINGS LIGHTEN UP EARLY
FRIDAY. SOME MINOR FLOODING IS POSSIBLE...REFER TO HYDRO SECTION
BELOW. HIGHS THURSDAY GENERALLY IN THE MID 70S. EPISODES OF
SHOWERS/TSTMS EXPECTED UNDER CLOUDY SKIES.

FRIDAY...LIKELY POPS FOR RAIN SHOWERS IN THE MORNING...THEN
SLOW/GRADUAL DRYING FROM NW-SE ACROSS THE REGION. SHOULD SEE SOME
PARTIAL SUNSHINE LATE IN THE DAY FROM THE CHAMPLAIN VALLEY WWD.
COOLER TEMPS WITH HIGHS IN THE LOW-MID 60S.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 450 AM EDT WEDNESDAY...LOTS OF UNCERTAINTY IN FCST AS WE
HEAD INTO THE HOLIDAY WEEKEND...AS LATEST TRENDS SHOW A MUCH
DEEPER/SLOWER SYSTEM FOR FRIDAY INTO SUNDAY. HAVE TRENDED TWD THE
00Z ECMWF AND 12Z GFS SOLUTIONS FOR THIS FCST...WHICH SUPPORTS THE
MENTION OF RAIN ON SATURDAY INTO SATURDAY NIGHT. IF CRNT TRENDS
CONT FOR A MUCH DEEPER AND SLOWER SYSTEM...ADDITIONAL SHOWERS
WOULD BE POSSIBLE FOR SUNDAY. LATEST 00Z ECMWF SHOWS NORTHERN AND
SOUTHERN STREAM INTERACTION BY 12Z SAT...WHICH HELPS TO PRODUCE A
CLOSED AND SLOW MOVING 5H/7H CIRCULATION OVER THE MID ATLANTIC
STATES. WHILE SFC LOW PRES TRACKS FROM NJ COAST TO THE GULF OF
MAINE BY 18Z SUNDAY. GIVEN THE POSITION AND TRACK OF CLOSED SYSTEM
AND ASSOCIATED SFC LOW PRES...EXPECT HEAVIEST QPF TO BE JUST SOUTH
AND EAST OF OUR CWA ON FRIDAY INTO SATURDAY. HOWEVER...BACKSIDE
DEFORMATION BAND OF ENHANCED MID LVL RH AND ASSOCIATED 850 TO
500MB LIFT IS EXPECTED TO DEVELOP. ITS EXTREMELY DIFFICULT TO
DETERMINE EXACT PLACEMENT AND MOVEMENT OF THESE BANDS AND THE
ASSOCIATED PRECIP...THEREFORE WL JUST MENTION CHC POPS FOR
SATURDAY INTO SATURDAY NIGHT. FEEL SYSTEM WL SLIDE JUST FAR ENOUGH
EAST BY SUNDAY TO KEEP FCST DRY ATTM. ON SUNDAY...AS SFC LOW PRES
TRACKS INTO THE GULF OF MAINE...LOOK FOR GUSTY NORTHWEST WINDS TO
DEVELOP. LATEST SOUNDINGS SHOW 85H WINDS BTWN 35 AND 45
KNOTS...WHICH WITH SOME MIXING WL SUPPORT GUSTS BTWN 25 AND 35
MPH..ESPECIALLY SUNDAY AFTN. PROGGED 85H TEMPS SUPPORT HIGHS ONLY
IN THE L/M 50S MTNS TO U50S/L60S FOR SAT AND SUNDAY. EXPECT A
RAW/CLOUDY AND BREEZY TYPE DAY ON SUNDAY...WITH BLW NORMAL TEMPS.
SFC HIGH PRES WL FINALLY BUILD INTO OUR CWA ON MONDAY INTO
TUES...WITH A SLOW CLRING TREND...ALONG WITH WARMER TEMPS. IF
SKIES CLR AND WINDS BECM LIGHT...PATCHY FROST WL BE POSSIBLE IN
THE COLDER MTN VALLEYS LATE THIS WEEKEND OR EARLY NEXT WEEK.

&&

.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
THROUGH 06Z THURSDAY...ONCE AGAIN ANOTHER CHALLENGING AVIATION
FCST WITH REGARDS TO POTENTIAL IFR CIGS/VIS THRU THIS MORNING.
CRNT OBS SHOW TAF SITES RANGING FROM VFR AT RUT TO MVFR AT
BTV/SLK/MSS AND IFR AT MPV/PBG. RADAR SHOWS BAND OF MODERATE RAIN
ACRS THE CPV...WHICH WL BE EAST AND SOUTH OF MPV/RUT TAF SITES BY
07Z. GIVEN 925MB WINDS OF 25 TO 35 KNTS...EXPECT STRATUS
DEVELOPMENT WITH IFR LIKELY AT MPV/MSS/SLK BY 08Z THIS MORNING.
MEANWHILE...SOUNDINGS SHOW PLENTY OF BL RH AT RUT/BTV/PBG...BUT
FEEL MVFR CONDITIONS WITH PERIODS OF IFR CIGS CAN BE EXPECTED TWD
MORNING. ANY IFR CIGS SHOULD SLOWLY DISSIPATE BY 15Z AT
MPV/MSS/SLK...AS SOUTHERLY WINDS DEVELOP. SFC BOUNDARY CONTS TO BE
DRAPED ACRS OUR TAF SITES THIS AFTN. THIS FRNT...COMBINED WITH SFC
HEATING/INSTABILITY WL PRODUCE MORE SCATTERED/NUMEROUS
SHOWERS/STORMS AFT 21Z TODAY...WITH MVFR TO BRIEF PERIODS OF IFR
CIGS/VIS LIKELY IN THE HEAVIER STORMS. IN ADDITION...BRIEF GUSTY
WINDS WL BE POSSIBLE. THIS SHOWERS WL WEAKEN TWD LATE EVENING WITH
AREAS OF LOW CLOUDS AND PATCHY FOG LIKELY DEVELOPING BY 06Z
THURSDAY...ESPECIALLY MSS/SLK/MPV.

OUTLOOK 06Z THURSDAY THROUGH SUNDAY...
UNSETTLED WX WITH OCCASIONAL SHOWERS/STORMS WL CONT FOR THURSDAY
INTO FRIDAY ACRS OUR TAF SITES. THE STRONGER SHOWERS/STORMS ON
THURS AFTN/EVENING ASSOCIATED WITH A SFC COLD FRNT WL PRODUCE MVFR
CONDITIONS...WITH BRIEF PERIODS OF IFR LIKELY. ALSO...ANY STORMS
WL HAVE THE POTENTIAL TO PRODUCE GUSTY SFC WINDS UP TO 40 MPH. AREAS
OF FOG AND LOW CLOUDS WL BE POSSIBLE ON THURSDAY NIGHT...WITH SOME
LOCALIZED IFR/LIFR LIKELY. SCATTERED SHOWERS MAY LINGER INTO EARLY
SATURDAY MORNING...BEFORE HIGH PRES SLOWLY BUILDS INTO THE REGION
BY SUNDAY. GUSTY NORTHWEST WINDS WL BE POSSIBLE OVER THE
WEEKEND...WITH AREAS OF LLVL TURBULENCE.

&&

.HYDROLOGY...
430AM WEDNESDAY...WIDESPREAD 1.0" TO 1.5" RAINFALL (WITH LOCALLY
HIGHER AMTS) HAS OCCURRED ACROSS THE NORTH COUNTRY DURING THE PAST
24-30 HOURS ASSOCIATED WITH SEVERAL EPISODES OF HEAVY SHOWERS AND
TSTMS. AN ADDITIONAL 1-2" RAINFALL IS FORECAST BETWEEN LATE
AFTN/EVENING SHOWERS AND TSTMS AND THE MORE WIDESPREAD RAIN AND
EMBEDDED TSTMS ON THURSDAY. WHILE ANTECEDENT SOIL CONDITIONS HAVE
BEEN DRY...AND VEGETATION IS FULLY ACTIVE...THE ADDITIONAL
RAINFALL WILL EVENTUALLY BRING THE POTENTIAL FOR STREET/POOR
DRAINAGE FLOODING. ASSOCIATED MINOR FLOODING WOULD MOST LIKELY
OCCUR DURING THE DAY THURSDAY AND INTO THURSDAY NIGHT. MAIN-STEM
RIVER FLOODING IS NOT FORECAST...BUT MAY NEED TO WATCH SOME OF THE
SMALLER RIVERS AND STREAMS THAT COULD LOCALLY EXCEED BANKFUL LATER
THURSDAY AND THURSDAY NIGHT.

&&

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

&&

$$
SYNOPSIS...BANACOS
NEAR TERM...BANACOS
SHORT TERM...BANACOS
LONG TERM...TABER
AVIATION...TABER
HYDROLOGY...