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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KCAR 202237
AFDCAR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
637 PM EDT MON MAY 20 2013

.SYNOPSIS...
WEAK HIGH PRESSURE WILL BUILD TOWARD THE REGION FROM THE NORTHWEST
OVERNIGHT AND TUESDAY AS A FRONTAL BOUNDARY REMAINS TO OUR SOUTH.
LOW PRESSURE WILL APPROACH WEDNESDAY AND CROSS THE REGION
THURSDAY.

&&

.NEAR TERM /THROUGH TUESDAY/...
-- Changed Discussion --
637 PM UPDATE: NEEDED TO ADJUST RAFL AND KEEP HIGHER POPS(80-90%)
ACROSS THE NORTHERN AND EASTERN AREAS. 21Z SFC ANALYSIS SHOWED
FRONTAL BOUNDARY DRAPED ACROSS THE CWA W/WEAK SFC LOW MOVING
ACROSS THE MID COAST OF MAINE WHILE ANOTHER LOW IS LOCATED NORTH
OF ST. LAWRENCE RIVER. LLVL CONVERGENCE AXIS IN SUPPORT OF THE
FRONT W/LIGHT RAIN AND DRIZZLE ACROSS THE NNE AREAS. CLEARING
ACROSS THE WEST-CENTRAL AND DOWNEAST AREAS W/TEMPERATURES IN THE
LOW TO MID 60S WHILE NNE AREAS WERE IN THE 50S.


PATCHY FOG IS POSSIBLE OVR THE PARTIAL CLRG AREA DUE TO SHALLOW
RADIATIONAL COOLING. WITH CLD CVR...PATCHY FOG AND RELATIVELY HIGH
DWPTS... OVRNGT LOWS WILL BE FAIRLY MILD.

WITH SOME DRYING BEHIND THE INITIAL S/WV RESULTING IN THE SHWRS
EARLIER TDY...NRN AND ERN PTNS OF THE FA SHOULD GET AT LEAST
PARTLY SUNNY SKIES BY MIDDAY TUE. ELSEWHERE...MID AND LOW CLDNSS
WILL HANG ON AS A WEAK S/WV ASSOCIATED WITH A WEAKENING CNVCTV
COMPLEX GRAZES SW PTNS OF THE FA WHERE WE MENTION A CHC OF SHWRS
TUE MORN INTO ERLY/MID AFTN. GIVEN THIS DISTRIBUTION OF CLDS
AND POPS BY TUE AFTN...WE XPCT A WEAKLY INVERTED S TO N GRAD
OF HI TEMPS THIS PD.
-- End Changed Discussion --

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
A COMPLEX AND UNSETTLED PATTERN WILL UNFOLD FOR THE MID TO LATE
WEEK TIME FRAME AS A SERIES OF DISTURBANCES CONTINUE TO TRACK EAST
ALONG A FRONTAL BOUNDARY OVER THE NORTHEAST.

CLOUDS INCREASE TUESDAY EVENING WITH RAIN DEVELOPING FROM WEST TO
EAST BY THE OVERNIGHT PERIOD AND CONTINUING INTO WEDNESDAY
MORNING BEFORE WINDING DOWN IN THE AFTERNOON AS THE DISTURBANCE
MOVES OUT. EXPECT GENERAL RAIN AMOUNTS OF ONE TO TWO THIRDS INCHES
BY THIS TIME WITH THIS FEATURE. DUE TO SIGNIFICANT CLOUD COVER
PERSISTING WEDNESDAY AFTERNOON ALONG WITH SCATTERED SHOWERS AND
AND E/SE WIND NORTH OF THE FRONTAL BOUNDARY NOT EXPECTING HIGHS
ABOVE THE MID TO HIGH 50S.

FOLLOWING A BRIEF RESPITE LATE DAY WEDNESDAY THE NEXT SYSTEM IN
ASSOCIATION WITH THE MAIN 500 MB TROUGH WILL MOVE IN FROM WEST TO
EAST OVERNIGHT. MODELS ARE STILL STRUGGLING TO RESOLVE HOW ENERGY
ASSOCIATED WITH THE TWO BRANCHES OF THE FLOW ALOFT WILL COME
TOGETHER AND THIS WILL SUBSEQUENTLY IMPACT THE EVOLUTION AND TRACK
OF THE LOW AT THE SURFACE. THE TRACK OF THE LOW WILL DETERMINE
WHETHER THE AREA WILL BREAK INTO THE WARM SECTOR THURSDAY AND SEE
MORE OF A SHOWER/THUNDERSTORM SITUATION VS. A TRACK FARTHER SOUTH
WHICH WOULD RESULT IN MUCH COOLER TEMPERATURES WITH A STEADIER
RAIN. AT THIS POINT CONTINUED TO LEAN WITH A MIDDLE GROUND
SOLUTION ADVERTISED BY THE 00Z ECMWF...BRINGING IN HIGH LIKELY TO
LOW END CATEGORICAL POPS FOR LATE WEDNESDAY NIGHT INTO THURSDAY.
ALSO INTRODUCED THE CHANCE OF THUNDERSTORMS FOR THURSDAY AFTERNOON
OVER CENTRAL AND INTERIOR PORTIONS OF THE SOUTH WITH RISK APPEARS
HIGHEST AT THIS TIME. FOR TEMPERATURES, USED A BLEND OF ALL
GUIDANCE ALONG WITH PREVIOUS FORECAST. THIS SOLUTION RESULTS IN
HIGHS RANGING FROM NEAR 60 NORTH TO AROUND 70 OVER INTERIOR
DOWNEAST LOCALS. AS MENTIONED, HOWEVER, THERE IS CONSIDERABLE
UNCERTAINTY REGARDING TEMPERATURES DUE TO THE UNCERTAIN TRACK OF
THE LOW.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
STILL SOME UNCERTAINTY WITH REGARD TO THE FORECAST FOR THURSDAY
NIGHT AND FRIDAY AS MEDIUM RANGE MODELS STILL NOT IN AGREEMENT
WITH REGARD TO TIMING/POSITION OF THE APPROACHING COLD FRONT. THE
12Z OPERATIONAL RUN OF THE GFS IS SLOWER IN PUSHING THE FRONT
ACROSS THE REGION THURSDAY NIGHT THROUGH FRIDAY WITH MORE IN THE
WAY OF CLOUDS AND SHOWERS. 00Z EC IS MORE PROGRESSIVE IN BRINGING
THE FRONT THROUGH LATER THURSDAY NIGHT WITH SHOWERS ENDING AND
IMPROVING CONDITIONS ON FRIDAY. AT THIS POINT...TOOK A BLEND OF
THE FASTER 00Z EC AND LESS PROGRESSIVE 12Z GFS WHICH PRETTY MUCH
KEPT CONTINUITY WITH PREVIOUS FORECAST. THUS...EXPECT THE CHANCE
OF SHOWERS INTO THE DAY FRIDAY MAINLY EARLY IN THE DAY.

THE GOOD NEWS IS THAT THE MEMORIAL DAY WEEKEND IS LOOKING MAINLY
DRY AT THIS POINT AS HIGH PRESSURE AT THE SURFACE BUILDS EAST.
ONLY FLY IN THE OINTMENT IS THAT THE MODELS ARE INDICATING AN UPPER
LEVEL TROF MOVING ACROSS THE REGION ON SATURDAY. THE COMBINATION
OF THE UPPER LEVEL TROF AND COLD POOL ALOFT MAY RESULT IN ENOUGH
INSTABILITY FOR A FEW SHOWERS ON SATURDAY BUT FOR NOW WILL CAP THE
POPS AT SLIGHT CHANCE. OTHERWISE A DRY WEATHER PATTERN IS EXPECTED
THROUGH THE WEEKEND.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: IFR AND MVFR CONDITIONS WILL LIKELY CONT ACROSS ALL TAF
SITES THRU THE REMAINDER OF THE AFTN. AFTWRDS...IT IS NOT CERTAIN
IF DRIER AIR FROM THE NW WILL RESULT IN FURTHER IMPROVEMENT WITH
CLGS AND VSBYS...OR NOT GOING INTO THE OVRNGT HRS. NRN TAF SITES
SHOULD THEN IMPROVE TO VFR BY MIDDAY...WITH DOWNEAST SITES ONLY
IMPROVING TO HIGH MVFR OR LOW VFR BY TUE AFTN DUE TO SHWRS IN THE
VCNTY THERE.

SHORT TERM: EXPECT IFR CONDITIONS TO DEVELOP TUESDAY NIGHT INTO
WEDNESDAY AS RAIN AND FOG MOVES IN. THIS ROUND OF STEADIER RAIN
MOVES OUT BY LATE WEDNESDAY HOWEVER MVFR/IFR CONDITIONS WILL
LIKELY CONTINUE TO BE AN ISSUE MUCH OF THE TIME RIGHT THROUGH
THURSDAY DUE TO CONTINUING STRATUS ALONG WITH THE APPROACH OF THE
NEXT SYSTEM BY THURSDAY.

VFR/MVFR CONDITIONS ARE LIKELY IN ANY SHOWERS THURSDAY NIGHT
THROUGH FRIDAY...OTHERWISE VFR EXPECTED.

&&

.MARINE...
NEAR TERM: WITH S WINDS SUBSIDED...WE WERE ABLE TO CANCEL THE SCA
FOR THE INNER HARBOR MZ052 AND CONVERTED THE THE SCA OVR THE OUTER
MZS TO AN SCA FOR HAZ SEAS DUE TO PERSISTENT 5 FT SWELL TIL 00Z...
AFT WHICH...WVS SHOULD SUBSIDE BLO 5 FT ALLOWING THE SCA THERE
TO BE LOWERED. NO HDLNS THEN XPCTD FOR THE REMAINDER OF THE OVRNGT
THRU TUE.

SHORT TERM: EXPECT REDUCED VISIBILITIES DUE TO RAIN AND FOG
TUESDAY NIGHT INTO WEDNESDAY. A STRONGER SYSTEM WILL MOVE IN
THURSDAY WITH SCA CONDITIONS LIKELY FOR BOTH WINDS AND SEAS.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...SMALL CRAFT ADVISORY FOR HAZARDOUS SEAS UNTIL 8 PM EDT THIS
     EVENING FOR ANZ050-051.

&&

$$
NEAR TERM...HEWITT/VJN
SHORT TERM...FITZSIMMONS
LONG TERM...DUDA
AVIATION...HEWITT/VJN/FITZSIMMONS
MARINE...HEWITT/VJN/FITZSIMMONS