Severe Thunderstorm Warning 48, NWS Caribou, ME

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
644 PM EDT THU JUL 18 2013

.SYNOPSIS...
HIGH PRESSURE WILL BRIEFLY BUILD ACROSS NORTHERN MAINE THIS
AFTERNOON THEN SHIFT EAST OF THE STATE TONIGHT AS A WARM FRONT
BEGINS TO MOVE BACK NORTHEAST ACROSS THE AREA. THIS WARM FRONT
WILL MOVE NORTHEAST OF THE REGION LATER FRIDAY THEN A STRONG COLD
FRONT WILL CROSS THE STATE LATER FRIDAY NIGHT INTO SATURDAY. A
DRIER AND COOLER CANADIAN AIRMASS WILL THEN BUILD INTO THE AREA ON
SUNDAY AND REMAIN INTO EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH FRIDAY/...
645 PM UPDATE...
A WEAK RIDGE OF HIGH PRESSURE COVERS NORTHERN MAINE. THE COLD
FRONT THAT CROSSED THE REGION LAST EVENING IS SOUTH OF THE CWA
EARLY THIS EVENING AND WILL BEGIN TO WORK BACK TO THE NORTH AS A
WARM FRONT LATER TONIGHT. THERE IS A BROKEN LINE OF SHOWERS THAT
EXTENDS FROM SOUTHERN PISCATAQUIS COUNTY TO CENTRAL WASHINGTON
COUNTY. A FEW MORE SHOWERS WITH EMBEDDED THUNDERSTORMS TO THE
SOUTH OF THIS LINE. ACROSS THE CROWN OF MAINE THE ATMOSPHERE IS
DRIER AND MORE STABLE. THE WARM FRONT WILL BRING THE SHOWERS AND
EMBEDDED STORMS TO THE NORTH OVERNIGHT...PROBABLY NOT REACHING FAR
NORTHERN MAINE UNTIL AFTER MIDNIGHT. ADDED IN SOME ISOLATED
THUNDER EARLY THIS EVENING TO THE SOUTH OF THE BROKEN LINE OF
SHOWERS...EXCEPT ALONG THE COAST WHERE IT SHOULD REMAIN STABLE.

PREVIOUS DISCUSSION...
A WARM FRONT WILL CROSS THE REGION TONIGHT AND REPLACE THE COOLER
AND DRIER AIR MASS WITH A WARMER AND MORE HUMID AIR MASS FOR
FRIDAY. THE WARM FRONT WILL BRING SHOWERS LATER TONIGHT WITH SOME
EMBEDDED THUNDERSTORMS THAT MAY PRODUCE HEAVY DOWNPOURS IN
NORTHERN ZONES BY DAYBREAK FRIDAY. THE CLOUDS WILL LIMIT LOWS TO
THE LOW TO MID 60S. THE WARM FRONTAL CLOUDS AND SHOWERS WILL
LINGER NORTH OF HOULTON IN THE MORNING AND KEEP TEMPERATURES
COOLER...LIMITING INSTABILITY. FURTHER SOUTH TOWARDS BANGOR
DOVER-FOXCROFT...LINCOLN AND MILLINOCKET...CLOUDS WILL BREAK UP
AND ALLOW HEATING TO BRING TEMPERATURES TO THE UPPER 80S WITH DEW
POINTS NEAR 70F. THIS IS EXPECTED TO PRODUCE SIGNIFICANT
INSTABILITY WITH THE POTENTIAL TO PRODUCE SEVERE THUNDERSTORMS TO
45000 FEET. CLEARING WILL REACH NORTHERN ZONES A BIT LATER IN THE
AFTERNOON AND PRODUCE LESS CAPE WITH HIGHS IN THE UPPER 70S TO LOW
80S. HOWEVER...A COLD FRONT WILL BE SAGGING SOUTHWARD FROM QUEBEC
AND SERVE AS A TRIGGER IN THESE NORTHERN ZONES. ALL AREAS WILL
HAVE IMPRESSIVE 0-1 AND 0-6KM SHEAR TO SUPPORT SEVERE STORMS. LOW
LCLS AND HODOGRAPHS SUGGEST THAT A ISOLATED TORNADO CANNOT BE
RULED OUT FRIDAY AFTERNOON. A STRONG LOW LEVEL JET...PWATS NEAR 2
INCHES...A DEEP WARM CLOUD LAYER AND CORFIDI VECTORS CONTINUE TO
HIGHLIGHT THE RISK OF URBAN AND SMALL STREAM FLOODING UNDER THE
STRONGER STORMS. COASTAL ZONES SHOULD BE UNDER THE INFLUENCE OF A
BRISK SOUTHERLY WIND THAT SHOULD AGAIN DAMPEN STORMS FOR THE
COASTAL ZONES AND HAVE NOT CARRIED SEVERE THUNDERSTORMS IN THESE
ZONES.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
CONVECTION WITH SEVERE POTENTIAL POSSIBLE IN SATURDAY AND THEN A
COOL DOWN.

THUNDERSTORMS WILL BE LIKELY INTO FRIDAY EVENING UP THROUGH
MIDNIGHT AS IT LOOKS ATTM W/THE PRE-FRONTAL BOUNDARY. STORMS WILL
CONTINUE TO HAVE THE POTENTIAL FOR DAMAGING WINDS, VERY HEAVY
RAINFALL WITH FLASH FLOODING A BIG POSSIBILITY. SB CAPES REACHING
WELL ABOVE 1500 J/KG AND LIS ABV -5 WILL LEND SUPPORT FOR TSTM
DEVELOPMENT. STRONG DIRECTIONAL/SPEED SHEAR W/GOOD TURNING UP
THROUGH 5K FT WILL LEAD TO THE POTENTIAL FOR SOME STORMS TO
ROTATE. THE MAIN AXIS WILL SHIFT FROM NORTHERN AREAS DURING THE
AFTERNOON TO THE CENTRAL HIGHLANDS AND INTERIOR SECTIONS OF
DOWNEAST MAINE THROUGH THE EVENING. DECENT VALUES OF 0-3KM
EHI(ENERGY HELICITY) SHOWS A POTENTIAL FOR SOME SPINNING/ROTATION.
ACTIVITY WILL WEAKEN AFTER 06Z AS THE FORCING MOVES INTO NEW
BRUNSWICK AND WEAKENS. TEMPERATURES WILL BE RATHER WARM FRIDAY
NIGHT NOT DROPPING MUCH BELOW THE MID AND UPPER 60S.

ANOTHER ROUND OF CONVECTION LOOKS TAKE PLACE AGAIN IN THE
AFTERNOON ON SATURDAY AS A POTENT COLD FRONT MOVES ACROSS THE
REGION. ATTM, THE CENTRAL HIGHLANDS AND DOWNEAST REGION LOOK TO
SEE THE BEST CHANCES FOR SEEING POTENTIAL FOR STRONG TO POSSIBLY
SEVERE TSTMS. THE SEVERE WEATHER THREAT WILL BE DAMAGING WINDS,
HEAVY RAINFALL AND HAIL. DAYTIME HIGHS FOR SATURDAY WILL BE IN THE
LOWER 80S ACROSS THE NORTH AND MID TO POSSIBLY UPPER 80S CENTRAL
AND DOWNEAST MINUS THE COAST AS A SSW WIND WILL HELP TO KEEP THE
IMMEDIATE COAST A BIT COOLER.

THE COLD FRONT IS EXPECTED TO CLEAR THE COAST SATURDAY NIGHT
W/HIGH PRES MOVING TOWARD THE AREA ON SUNDAY. TEMPERATURES WILL BE
MUCH COOLER BY SUNDAY MORNING. WE ARE TALKING MORNING LOWS OF
UPPER 40S TO LOW 50S NORTH AND WEST AND MID TO UPPER 50S CENTRAL
AND DOWNEAST. SUNDAY'S HIGH TEMPERATURES WILL BE SOME 10-15
DEGREES COOLER THAN THEY HAVE BEEN THE PAST SEVERAL DAYS.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
A HIGH PRESSURE RIDGE WILL DOMINATE THE WEATHER AT THE START OF
THE EXTENDED PERIOD AND REMAIN ACROSS THE AREA THROUGH MONDAY
NIGHT. TUES MRNG THE RIDGE WILL MOVE EAST AS A NEW LOW PRESSURE
SYSTEM MOVE INTO THE ERN GREAT LAKES REGION...THEN INTO ME EARLY
EVNG TUES. BOTH THE GFS AND ECMWF ARE SHOWING A LOW ALONG THE
ATLANTIC COAST MOVING NORTH ALONG THE COAST...AND A COLD FRONT
MOVING EAST THROUGH THE GREAT LAKES REGION. THE LOW WILL MOVE UP
THE COAST INTO THE GULF OF MAINE OVERNIGHT TUES INTO WED. A WEAK
RIDGE OF HIGHER PRESSURE WILL BRIEFLY BUILD IN...BEFORE THE COLD
FRONT MOVES INTO NW ME THURS MRNG. UNSETTLED WEATHER WILL CONTINUE
THROUGH THE END OF THE PERIOD...AS THE COLD FRONT BECOMES
STATIONARY OVER THE AREA AS THE SURFACE FRONT MOVES UP AGAINST THE
UPPER LEVEL RIDGE AND STALLS. SHOWERS AND THUNDERSTORMS WILL
TRANSIT ALONG THE BOUNDARY.

LOADED A BLEND OF THE LAMP/RUC/NAM FOR HRLY T/DP/MAX/MIN TEMP.
ALL MODEL BLEND FOR WND/SKY/POP...ADDED 15 PERCENT TO WINDS FOR
GUSTS OVER LAND...20 PERCENT OVER COASTAL WATERS.

&&

.AVIATION /22Z THURSDAY THROUGH TUESDAY/...
NEAR TERM: VFR THIS EVENING. IFR CIGS AND IFR VIS IN HEAVY SHOWERS
WILL MOVE INTO ALL AREAS LATER TONIGHT AND REMAIN INTO MID
MORNING. NORTHEASTERN TERMINALS SUCH AS PQI...CAR AND FVE WILL BE
THE LAST TO CLEAR TO VFR BY EARLY AFTERNOON. SEVERE THUNDERSTORMS
WILL BE A MAJOR AVIATION HAZARD FRIDAY AFTERNOON WITH STORMS TO
FL450 WITH HAIL AND WIND GUSTS TO 60 MPH POSSIBLE...MOST LIKELY AT
MLT...BGR...HUL AND LEAST LIKELY AT BHB.

SHORT TERM: MVFR/IFR POTENTIAL FOR ALL TERMINALS FRIDAY NIGHT
W/LLWS DUE TO TSTMS. SOME STORMS COULD BE STRONG TO SEVERE AWAY
FROM THE COAST. AN AWW COULD BE NEEDED FOR KBGR. ANOTHER ROUND OF
CONVECTION ON SATURDAY WILL LEAD TO MVFR AND PERHAPS IFR W/LLWS.
IMPROVING CONDITIONS LATER SATURDAY NIGHT INTO SUNDAY W/VFR.

&&

.MARINE...
NEAR TERM: SOME FOG IS POSSIBLE LATER TONIGHT INTO FRIDAY
MORNING...BUT HAVE NOT INCLUDED IN FORECAST FOR NOW. WINDS WILL
PICK UP FROM THE SW LATER FRIDAY...BUT ADJUSTED DOWN FROM
GUIDANCE. AN SCA IS POSSIBLE FOR THE INTRACOASTAL ZONE FRIDAY
AFTERNOON AS STABILITY FACTORS WILL NOT BE AS SIGNIFICANT.

SHORT TERM: SCA HEADLINES MAY BE NEEDED DUE TO AN INCREASING SWELL
AS SHOWN BY THE LATEST WAVE GUIDANCE. STAYED CLOSE TO THE MIDNIGHT
CREW'S ASSESSMENT OF SEAS BUILDING TO 5-6 FT LATER FRIDAY NIGHT
CONTINUING THROUGH SATURDAY NIGHT. A BRIEF SURGE OF WINDS TO 20
KTS POSSIBLE FRIDAY EVENING.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.

&&

NEAR TERM...CB/MCW
SHORT TERM...HEWITT
LONG TERM...NORTON
AVIATION...CB/MCW/HEWITT
MARINE...CB/MCW/HEWITT

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE CARIBOU ME
421 PM EDT THU JUL 18 2013

MEZ001>006-010-011-015>017-029>032-192030-
NORTHWEST AROOSTOOK-NORTHEAST AROOSTOOK-NORTHERN SOMERSET-
NORTHERN PISCATAQUIS-NORTHERN PENOBSCOT-SOUTHEAST AROOSTOOK-
CENTRAL PISCATAQUIS-CENTRAL PENOBSCOT-SOUTHERN PENOBSCOT-
INTERIOR HANCOCK-CENTRAL WASHINGTON-COASTAL HANCOCK-
COASTAL WASHINGTON-SOUTHERN PISCATAQUIS-NORTHERN WASHINGTON-
421 PM EDT THU JUL 18 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL MAINE...NORTH
CENTRAL MAINE...NORTHERN MAINE...SOUTHEAST MAINE AND WEST CENTRAL
MAINE.

.DAY ONE...TONIGHT.

HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

THERE IS POTENTIAL FOR SEVERE THUNDERSTORMS FRIDAY INTO FRIDAY
EVENING. THE MAIN SEVERE WEATHER THREAT WILL BE DAMAGING WIND
GUSTS IN EXCESS OF 58 MPH AND THE POTENTIAL FOR SOME STORMS TO
HAVE ROTATION. TORRENTIAL RAINFALL IS ALSO EXPECTED WITH THE
THUNDERSTORMS WHICH COULD LEAD TO FLASH FLOODING. THE AREAS TO SEE
THE HIGHEST THREAT FOR SEVERE THUNDERSTORMS INCLUDE NORTHERN AND
CENTRAL MAINE AND POSSIBLY INTERIOR DOWNEAST MAINE.

ANOTHER ROUND OF SEVERE THUNDERSTORMS WITH THE POTENTIAL FOR ARE
POSSIBLE AGAIN ON SATURDAY AS A COLD FRONT MOVES SOUTHWARD ACROSS
THE AREA WITH THE HIGHEST THREAT ACROSS CENTRAL AND DOWNEAST MAINE.

STAY TUNED FOR UPDATES ON THIS DEVELOPING SITUATION.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

ANZ050>052-192030-
COASTAL WATERS FROM EASTPORT ME TO SCHOODIC POINT ME OUT 25 NM-
COASTAL WATERS FROM SCHOODIC POINT ME TO STONINGTON ME OUT 25 NM-
INTRACOASTAL WATERS FROM SCHOODIC POINT ME TO STONINGTON ME-
421 PM EDT THU JUL 18 2013

THIS HAZARDOUS WEATHER OUTLOOK IS FOR ATLANTIC COASTAL WATERS.

.DAY ONE...TONIGHT.

HAZARDOUS WEATHER IS NOT EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

HEWITT