HAMweather.com Area Forecast Discussion for County Warning Area CAR

Thu, 16 Feb 2012 07:46:56 GMT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
1251 AM EST THU FEB 16 2012

.SYNOPSIS...
WEAK HIGH PRESSURE WILL BUILD ACROSS THE REGION TONIGHT AND THEN
MOVE EAST OF THE REGION THURSDAY. LOW PRESSURE FROM CENTRAL CANADA WILL
TRACK THROUGH QUEBEC FRIDAY AND THEN WILL REFORM OVER THE EASTERN
MARITIMES FRIDAY NIGHT. HIGH PRESSURE FROM CENTRAL CANADA WILL THEN
SLOWLY BUILD TOWARD THE REGION THIS WEEKEND WHILE LOW PRESSURE
FROM THE SOUTHEAST STATES TRACKS WELL SOUTH OF THE REGION.

.NEAR TERM /THROUGH THURSDAY/...
UPDATE...ADJUSTED MIN TEMPS UP ESPECIALLY ACROSS THE WEST AND
HIGHER TERRAIN. POPS WERE ADJUSTED AS WELL TO TO BRING 30-40% INTO
NORTHERN AND CENTRAL AREAS PER LATEST RADAR TRENDS. SKY GRIDS ARE
A BLEND OF THE NAM12 AND GEM SHOWING OVC CONDITIONS W/CLEARING
MOVING INTO SWRN SECTIONS BY DAYBREAK. THIS MATCHES WELL W/THE
LATEST SATL IR IMAGERY.

PREVIOUS DISCUSSION...
WEAK SURFACE HIGH PRESSURE BUILDING OVER THE
REGION TONIGHT WILL KEEP MOST OF THE STATE DRY THROUGH TOMORROW.
THE ONLY CAVEAT IS AN UPPER SHORTWAVE THAT WILL MOVE ALONG THE
SAINT JOHN VALLEY TONIGHT AND TOMORROW MORNING. THIS WILL PRODUCE
SOME LIGHT SNOW SHOWERS OVER NORTHERN MAINE. LITTLE TO NO SNOW
ACCUMULATION IS EXPECTED. INCREASING CLOUDS WILL KEEP TEMPERATURES
ON THE MILDER SIDE AGAIN TONIGHT WITH MOST LOCATIONS REMAINING IN
THE LOWER TO MID 20S.

THE ILL-DEFINED RIDGE WILL BEGIN TO SHIFT EAST OF NORTHERN NEW 
ENGLAND TOMORROW WHILE THE AFOREMENTIONED SHORTWAVE MOVES INTO NEW 
BRUNSWICK. THE SNOW SHOWERS WILL GRADUALLY COME TO AN END BY EARLY 
AFTERNOON. INCREASING SOUTH FLOW AND SUNSHINE TOMORROW AFTERNOON 
WILL ALLOW FOR ANOTHER NICE DAY. HIGHS WILL RANGE FROM THE MID 30S 
IN THE CROWN TO AROUND 40 DOWNEAST.

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
MODELS NOW APPEAR TO BE MORE PROGRESSIVE WITH THE S/WV MOVG ENE
FROM THE GREAT LKS LATE THU NGT AND FRI...AND SHOWING LESS
TENDENCY FOR THE UPPER TROF TO CLOSE ALF IN THE MID TO UPPER LVLS
S OF THE ST JOHN VLY...SO IT APPEARS THIS EVENT IS LEANING ON THE
LGT QPF SIDE WITH MOST IF NOT ALL OF THE QPF DROPPED DURING A
QUICK WARM ADVCN PHASE FRI. IN ADDITION...MODELS HAVE BACKED OFF
ON THE AMOUNT OF SECONDARY CYCLOGENESIS ALG OVR THE GULF OF ME IN
THE VICINITY OF THE ME COAST...SO IT APPEARS LLVL MARITIME AIR MAY
BE ABLE TO WORK FURTHER N THAN PREVIOUSLY THOUGHT DURING THE DAY
FRI. THIS CUTS DOWN ON SN-LIQ EQIV RATIOS FOR THIS EVENT AS SN
WILL MIX OR EVEN CHG TO ALL RN AS FAR N AS E CNTRL PTNS OF THE FA
BY FRI AFTN...WITH THE CHGOVR OCCURRING EARLIEST ALG THE COAST BY
MID MORN. EVEN OVR NE PTNS OF THE FA...WITH HI TEMPS AT OR JUST
ABV FZG FRI AFTN...SN-LIQ EQUIV RATIOS WILL LIKELY BE LESS THAN
10:1 MIDDAY THRU THE MID AFTN HRS FRI. STEADY PRECIP THEN APPEARS
TO MOVE E OF THE FA BY FRI EVE...LEAVING TYPICAL COLD ADVCN SCT SN
SHWRS MSLY ACROSS THE N AND W FOR FRI NGT.

GIVEN BOTH LESSER QPF AND LOWER SN-LIQ EQUIV RATIOS FOR MOST OF
THE FA WITH THIS EVENT... MOST LOCATIONS ATTM WILL LIKELY ONLY
RECEIVE TOTALS 1 TO 2 INCHES OF SN...WITH LESSER AMOUNTS DOWNEAST
DUE TO GREATER PERCENTAGE OF RNFL. WE KEPT POPS CATEGORICAL...BUT
CAPPED THEM AT 80 PERCENT DUE TO 6HRLY QPF TOTALS HARDLY REACHING
0.10 INCHES IN THE 06-12 AND 12 TO 18Z PDS FRI.

SAT SHOULD BE MCLDY N AND W AND PTLY TO MSLY SUNNY S...WITH ANY SN
SHWRS ACROSS N AND WRN PTNS OF THE FA ENDING DURING THE MORN.
TEMPS ALL PDS WILL BE QUITE MILD...WITH SAT HI TEMPS A LITTLE
CLOSER TO CLIMO ACROSS NRN AND WRN PTNS OF THE FA.

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AT THE START OF THE EXTENDED PERIOD THE MODELS ARE IN GOOD
GENERAL AGREEMENT. A LOW IN THE CANADIAN MARITIMES WITH A TROUGH
EXTENDING WEST INTO QUEBEC. A LOW ALONG THE GULF OF MEXICO COAST
AND A WEAK HIGH PRESSURE RIDGE BUILT ACROSS THE LOCAL AREA. THE
GFS SHOWS A CLOSED LOW OVER THE CENTRAL GREAT LAKES REGION. THE
ECMWF SHOWS A WEAKNESS IN THE RIDGE IN THE SAME AREA. BY SUNDAY
MORNING THE MODELS DIVERGE...THE GFS DEEPENS THE LOW ALONG THE
GULF COAST AND MOVES IT TO THE COAST OF VIRGINIA. THE GFS ALSO
DEEPENS THE LOW OVER THE CENTRAL GREAT LAKES AND MOVES IT EAST
INTO THE ERN GREAT LAKES REGION. THE RIDGE REMAINS OVER THE LOCAL
AREA. THE ECMWF MOVE THE LOW ALONG THE GULF COAST EAST TO THE
COAST OF GEORGIA. THE RIDGE EXPANDS TO ENCOMPASS ALL OF THE
CENTRAL AND NE STATES. THE GFS BY SUNDAY EVENING MOVES THE LOW NE
INTO THE CAPE COD REGION COMBINING THE ENERGY OF THE TWO LOWS INTO
RAPIDLY DEEPENING SYSTEM. THE ECMWF CONTINUES TO MOVE THE LOW OFF
THE COAST OF GEORGIA...THE HIGH PRESSURE RIDGE WILL ENCOMPASS ALL
OF THE CENTRAL AND EASTERN STATES EXCEPT THE CAROLINAS. BY MONDAY
MORNING THE GFS MOVES THE LOW EAST TO SRN NOVA SCOTIA. A HIGH
PRESSURE RIDGE BUILT ACROSS ALL EXCEPT NRN NEW ENGLAND. THE ECMWF
MAINTAINS THE HIGH PRESSURE RIDGE ACROSS THE CENTRAL AND EASTERN
STATES. BOTH MODELS SHOW A NEW LOW IN WESTERN KANSAS. BY MONDAY
NIGHT THE PRIMARY LOW ON THE GFS WILL BE INTO THE CANADIAN
MARITIMES...HIGH PRESSURE BEGINS TO BUILD INTO NORTHEAST. THE
ECMWF CONTINUES THE HIGH PRESSURE RIDGE...WITH THE NEW LOW OVER
CENTRAL KANSAS. BY TUESDAY MORNING THE MODELS ARE BACK TO A
REASONABLE AGREEMENT. A HIGH PRESSURE RIDGE ACROSS THE EASTERN
SEABOARD...A LOW PRESSURE SYSTEM ACROSS THE WESTERN GREAT LAKES
REGION. BY WEDNESDAY MORNING THE RIDGE BREAKS DOWN A LOW PRESSURE
SYSTEM OVER HUDSON BAY WITH A BROAD TROUGH EXTENDING SW INTO NRN
TEXAS. BY WEDNESDAY EVENING THE MODELS HAVE DIVERGED AGAIN. THE
GFS SHOWS A DEEPENING LOW OVER THE CHICAGO AREA WITH AN ASSOCIATED
FRONT EXTENDING TO THE GULF OF MEXICO. THE ECMWF SHOW A LOW ALONG
THE COAST OF VIRGINIA. WITH A WARM FRONT EXTENDING INTO DOWNEAST
MAINE. BY THE END OF THE PERIOD BOTH MODELS MOVE THE FRONT INTO
THE AREA.

AT THIS POINT IT APPEARS THAT THE 12Z OPNL GFS IS TO AGGRESSIVE
WITH THE DEVELOPMENT OF THE LOW ON SUNDAY AND MONDAY. HAVE TONED
DOWN THE POPS FOR SUNDAY AND MONDAY AS PER THE 12Z ENS MEAN GFS
POPS.

LOADED GMOS...ADJUSTED THE SKY AND POP GRIDS TO BETTER SUPPORT
ONE ANOTHER. ADJUSTED THE TEMPS AND POP GRIDS BLENDED THEM WITH
THE ECMWF FOR SUNDAY AND MONDAY. LOADED NAWAVE 4 FOR SEAS IN THE
COASTAL WATERS ADJUSTED SEAS DOWN BY ABOUT 4 TO 6 FEET FOR SUNDAY
AND MONDAY DUE TO THE GFS AGGRESSIVE HANDLING OF THE LOW. SUNDAY
AND MONDAY BLENDED GMOS AND ECMWF...PLUS 15 PERCENT FOR WIND GUSTS
OVER LAND...20 PERCENT OVER WATER.

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
NEAR TERM: MAINLY VFR EXPECTED THROUGH THURSDAY. SCATTERED SNOW 
SHOWERS AND MVFR CEILINGS WILL MOVE IN TOWARD MIDNIGHT TONIGHT 
ESPECIALLY AT THE NORTHERN TERMINALS. THE SHOWERS AND CLOUDS WILL 
BEGIN TO DECREASE LATE THURSDAY MORNING FROM NORTH TO SOUTH AND 
EXPECT ALL SITES TO ONCE AGAIN BE VFR AFTER 18Z. 

SHORT TO LONG TERM: VFR BEGINNING THU EVE...LOWERING TO MVFR ALL
SITES LATE THU NGT IN LGT SN AND THEN IFR/LOW MVFR ALL SITES FRI
IN LGT SN N AND MIXED PRECIP OR RAIN DOWNEAST SITES. ALL SITES
IMPROVING TO HI MVFR CIGS FRI NGT...WITH DOWNEAST SITES BECOMING
VFR BY SAT MORN. ALL SITES SHOULD BE VFR SAT NGT THRU MON ATTM.

.MARINE...
NEAR TERM: HIGH PRESSURE BUILDING OVER THE WATERS WILL KEEP
CONDITIONS BELOW SCA LEVELS THROUGH THURSDAY. NO HEADLINES WILL BE
NEEDED.

SHORT TERM: NEAR SCA WINDS AND SEAS ARE POSSIBLE LATE FRI NGT INTO
SAT BEHIND FRI'S WEAK LOW PRES SYSTEM. OTHERWISE...NO HDLNS ANTICIPATED
IN THE PTN OF THE CWF. WE USED A BLEND OF OPNL 12Z NAM...GFS AND
CANGEM ALG WITH 12Z GMOS FOR WINDS AND A BLEND OF WW3...SWAN NAM
AND SWAN GFS FOR WV HTS.

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