AFDCAR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
1109 PM EDT FRI JUL 8 2011

.SYNOPSIS...
A COLD FRONT WILL CROSS THE REGION OVERNIGHT THROUGH
SATURDAY...WHILE LOW PRESSURE TRACKS TO THE SOUTH. HIGH
PRESSURE WILL BUILD ACROSS THE REGION SATURDAY NIGHT THROUGH
SUNDAY.
&&

.NEAR TERM /THROUGH SATURDAY/...
UPDATE...
A COLD FRONT WILL REACH NORTHWEST MAINE OVERNIGHT WHILE LOW PRESSURE
TRACKS SOUTH OF THE GULF OF MAINE. SCATTERED SHOWERS AND POSSIBLY
AN ISOLATED THUNDERSTORM WILL OCCUR ACROSS MUCH OF THE FORECAST
AREA OVERNIGHT. SHOWERS COULD BE MORE EXTENSIVE ALONG THE DOWNEAST
COAST WHICH COULD BE CLIPPED WITH THE NORTHERN EDGE OF THE
PRECIPITATION SHIELD FROM THE LOW TRACKING SOUTH OF THE REGION.
HAVE UPDATED THE FORECAST TO ADJUST FOR CURRENT CONDITIONS AND
INCREASE SHOWER CHANCES ALONG THE DOWNEAST COAST. OVERNIGHT LOW
TEMPERATURES WILL RANGE FROM THE MID TO UPPER 50S ACROSS THE
REGION.

PREVIOUS DISCUSSION...
HIGH PRESSURE WILL MOVE EAST TONIGHT WHILE CLOUDS THICKEN AHEAD OF A
WEAK TROUGH MOVING IN FROM THE WEST. GUIDANCE STILL SHOWS TWO LOW
CENTERS WITH THIS TROUGH...ONE TO OUR NORTH ACROSS QUEBEC AND
ANOTHER MOVING NORTHEAST FROM THE MID ATLANTIC COAST. MOST OF THE
RAINFALL WITH THIS TROUGH IS EXPECTED TO BE CONCENTRATED NEAR THE
LOW CENTERS TO OUR NORTH AND SOUTH WITH LITTLE IN BETWEEN SO ONLY
MENTIONING SCATTERED SHOWERS FOR LATE TONIGHT INTO SATURDAY
MORNING. MODELS SHOW SOME ELEVATED CAPE LATE TONIGHT INTO SATURDAY
MORNING SO MENTIONED ISOLATED THUNDERSTORMS THROUGHOUT THE AREA
OVERNIGHT. GUIDANCE THEN SHOWS A BIT STRONGER CAPE DOWNEAST DURING
THE MIDDAY ON SATURDAY. SOME THUNDERSTORMS WILL BE POSSIBLE AS THE
TROUGH HANGS BACK OVER DOWNEAST AREAS THROUGH MIDDAY SATURDAY.
DRIER AIR SHOULD FOLLOW WITH CLEARING SATURDAY AFTERNOON AS THE
TROUGH CONTINUES EAST AND AWAY. SOME CUMULUS WILL BUBBLE UP ACROSS
NORTHERN AND CENTRAL AREAS ON SATURDAY.
&&

.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
SATURDAY NIGHT INTO SUNDAY WILL BE DRY WITH THE REGION BETWEEN
SYSTEMS. MODELS DIFFER FROM SUNDAY EVENING THROUGH MONDAY. NAM
BRINGS A SHORTWAVE ACROSS THE REGION WITH STRONGEST IMPACTS FROM
ISENTROPIC LIFT ACROSS THE CROWN OF MAINE SUNDAY EVENING AND
OVERNIGHT...THEN QUICKLY MOVING THAT SHORTWAVE EAST-NORTHEAST. THERE
APPEARS TO BE SOMEWHAT OF A DISCONNECT AS THE ISENTROPIC LIFT
PROGGED IS STRONGER THAN WOULD BE THOUGHT LOOKING AT THE VORTICITY
FIELD ASSOCIATED WITH THAT SHORTWAVE. ECMWF IS SIMILAR BUT NOT QUITE
AS STRONG. THE GFS HOLDS OFF ON PRECIP UNTIL MONDAY...WITH BEST JET
DYNAMICS HOLDING OFF UNTIL MONDAY NIGHT. WITH THE EXCEPTION OF THE
REGION OF ISENTROPIC LIFT MODELS DO NOT SHOW A STRONG SHORTWAVE
ENERGY MOVING THROUGH THE FLOW AT 500MB UNTIL LATE MONDAY NIGHT INTO
TUESDAY. HAVE BUMPED UP POPS SLIGHTLY ACROSS FAR NORTHWEST MAINE
SUNDAY NIGHT...WITH SLIGHT/LOW CHANCE POPS ACROSS THE REST OF MAINE
DURING THE DAY MONDAY. SOUTHWESTERLY-WESTERLY WINDS IN THE LOWER
LEVELS...AND ASSOCIATED WARM AIR ADVECTION WILL PUSH AFTERNOON
TEMPERATURES WELL INTO THE 70S AND 80S.
&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
THE THREAT OF THUNDERSTORMS WILL BEGIN THE LONG TERM PERIOD. A
COLD FRONT IS EXPECTED TO CROSS THE AREA MONDAY NIGHT INTO TUESDAY
MORNING. IT SEEMS AS IF THE INSTABILITY WILL LAST THROUGH THE
NIGHT ON MONDAY SO WILL CARRY THUNDERSTORMS MONDAY NIGHT THROUGH
TUESDAY. THE UPPER LEVEL SUPPORT WILL BE THERE FOR THUNDERSTORMS
ALL MONDAY NIGHT INTO TUESDAY. THE THREAT SHOULD BEGIN IN THE
NORTHWEST ZONES MONDAY EVENING THEN PROGRESS ACROSS THE STATE
MONDAY NIGHT AND TUESDAY. RIGHT NOW THE MAIN THREAT FROM THIS
SYSTEM WILL BE STRONG STRAIGHT LINE WINDS WITH ANY THUNDERSTORMS
THAT FORM AHEAD OF THE FRONT AS WELL AS WITH A POSSIBLE LINE OF STORMS
WITH THE FRONT ITSELF. THE TIMING OF THIS FRONT IS VERY IMPORTANT
IN HOW INTENSE THESE STORMS CAN GET. IF THE FRONT SLOWS AND
CROSSES THE STATE IN THE AFTERNOON TUESDAY ALLOWING FOR MORE
HEATING THE STORMS COULD BE MORE INTENSE. THE OPPOSITE SHOULD
HAPPEN IF THE FRONT MOVES THOUGH EARLY TUESDAY MORNING. THIS WILL
HAVE TO BE WATCHED IN FUTURE FORECAST CYCLES. AFTER THE FRONT
MOVES THROUGH ON TUESDAY...HIGH PRESSURE MOVES IN FOR THE REST OF
THE WEEK BRINGING US PLEASANT WEATHER.
&&

.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
NEAR TERM: GENERALLY VFR CONDITIONS ARE EXPECTED ACROSS NORTHERN
AREAS OVERNIGHT THROUGH SATURDAY...THOUGH MVFR CONDITIONS COULD OCCUR
WITH ANY SHOWERS OR THUNDERSTORMS. CONDITIONS DOWNEAST WILL LOWER
TO MVFR/IFR LEVELS...WITH OCCASIONAL LIFR LEVELS...OVERNIGHT.
MVFR/IFR CONDITIONS ARE EXPECTED DOWNEAST EARLY SATURDAY...IMPROVING
TO VFR LEVELS DURING THE AFTERNOON.

SHORT TERM: OUTSIDE OF ANY THUNDERSTORM ACTIVITY...PREDOMINATELY VFR
CONDITIONS EXPECTED THROUGH THE 00Z SUNDAY TO 00Z MONDAY TIME FRAME.
GENERALLY VFR CONDITIONS ARE EXPECTED MONDAY THROUGH
TUESDAY...THOUGH MVFR CONDITIONS ARE POSSIBLE WITH ANY SHOWERS OR
THUNDERSTORMS. VFR CONDITIONS ARE EXPECTED WEDNESDAY.
&&

.MARINE...
NEAR TERM: WINDS/SEAS ARE EXPECTED TO REMAIN BELOW SMALL CRAFT
ADVISORY LEVELS OVERNIGHT THROUGH SATURDAY. VISIBILITIES WILL BE
REDUCED IN ANY SHOWERS/THUNDERSTORMS OR PATCHY FOG OVERNIGHT
THROUGH SATURDAY.

SHORT TERM: NO ISSUES EXPECTED SATURDAY NIGHT THROUGH MONDAY. BY MONDAY
NIGHT INTO TUESDAY...WAVE HTS WILL PROBABLY EXCEED SMALL CRAFT
ADVISORY CRITERIA WITH ANOTHER ROUND OF THUNDERSTORMS POSSIBLE.
&&

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

&&

$$
NEAR TERM...BLOOMER/NORCROSS