214
FXUS61 KCAR 130653
AFDCAR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CARIBOU ME
253 AM EDT TUE AUG 13 2013
.SYNOPSIS...
LOW PRESSURE FROM THE GREAT LAKES WILL APPROACH THROUGH SOUTHERN
QUEBEC TODAY...THEN TRACK INTO THE SAINT JOHN VALLEY TONIGHT AND
INTO GULF OF SAINT LAWRENCE ON WEDNESDAY PRODUCING SHOWERY AND
UNSETTLED CONDITIONS. COOL AND DRIER CANADIAN HIGH PRESSURE WILL
RETURN FOR LATE WEEK...WITH A WARM UP LIKELY FOR THE WEEKEND.
&&
.NEAR TERM /THROUGH TONIGHT/...
AN UPPER TROUGH CURRENTLY SPINNING OVER EASTERN ONTARIO WILL PUSH
SOUTHEAST INTO QUEBEC TODAY, THEN MOVE INTO NORTHERN NEW ENGLAND
TONIGHT. MEANWHILE, THE SURFACE LOW AND COLD FRONT ASSOCIATED WITH
THIS SYSTEM WILL APPROACH OUR NORTHWESTERN BORDER TODAY. WIDESPREAD
SHOWERS ARE EXPECTED TO MOVE INTO WESTERN PORTIONS OF THE FORECAST
AREA THIS MORNING, THEN SPREAD EASTWARD THROUGH THE DAY. THICKENING
CLOUD COVER WILL LIMIT INSTABILITY THIS AFTERNOON, BUT PROGGED CAPES
OF 300-500 J/KG SHOULD BE ENOUGH TO ALLOW FOR A FEW RUMBLES OF
THUNDER. HIGHS WILL BE ON THE COOL SIDE FOR THIS TIME OF YEAR,
RANGING FROM THE MID AND UPPER 60S NORTH TO AROUND 70 SOUTH.
FOR TONIGHT...A SECONDARY SURFACE LOW WILL DEVELOP OFF THE NEW
ENGLAND COAST AND LIFT TOWARD NOVA SCOTIA AS THE UPPER TROUGH DIGS
INTO NORTHERN NEW ENGLAND. AS SUCH, FAR DOWNEAST AND COASTAL AREAS
HAVE THE BEST CHANCES TO SEE PRECIPITATION THIS EVENING INTO THE
FIRST PART OF TONIGHT. MEANWHILE, THE MAIN AREA OF SHOWERS WILL LIFT
NORTH TOWARD THE SAINT JOHN VALLEY. OVERNIGHT LOWS WILL BE IN THE
50S AREAWIDE.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
WELL...00Z MODELS ARE IN BETTER AGREEMENT LATE TNGT THEN YSTDY ATTM...
AGREEING MORE WITH THE ECMWF/UKMET MODEL RUNS ADVERTISED YSTDY ATTM.
THIS MEANS SHWRS AND UNSETTLED CONDITIONS WILL BE MUCH SLOWER TO
CLR AWAY FROM CNTRL AND SPCLY NRN PTNS OF THE FA ON WED AS AN
UPPER TROF/CLOSED LOW AND ASSOCIATED SFC LOW SLOWLY TRACK ACROSS
FAR NRN ME FROM SRN QB. FOR THIS REASON...WE HOLD LIKELY POPS THRU
MOST OF THE DAY WED. IN FACT...DUE TO STEEP MID LVL LAPSE RATES
ASSOCIATED WITH THE COLD CORE ALF OF THE UPPER TROF/LOW...WE
HAD TO INTRODUCE THE CHC OF AFTN TSTMS...WITH POTENTIAL AFTN
CAPES RANGING FROM 500 TO 1000 J/KG. WITH LOWERING FZG LVLS WITH
THE UPPER LOW...SMALL HAIL WILL BE POSSIBLE WITH TSTMS IF THERE
IS SOME MORN SUNSHINE TO DESTABILIZE THE ATMOSPHERE ENOUGH BY
AFTN. GIVEN THE UNCERTAINTY OF ANY SUNSHINE ATTM FOR WED...WE
WILL HOLD OFF ON ANY ENHANCED TSTM HAIL WORDING FOR NOW. HI TEMPS
WED AFTN WILL LIKELY SHOW A GREATER THAN CLIMO N TO S GRADIENT DUE
TO THE POTENTIAL OF GREATER CLD AND SHWR CVRG ACROSS THE N COMPARED
TO DOWNEAST PTNS OF THE REGION.
SHOWERS SHOULD SLOWLY DIMINISH AND THEN END ACROSS THE FA WED EVE
AS THE SFC AND UPPER LOW MOVE ENE AWAY INTO THE GULF OF ST LAWRENCE.
W WINDS...WHICH WILL INCREASE LATE WED AFTN AND ERLY EVE
IMMEDIATELY BEHIND THE LOW...WILL SLOWLY SUBSIDE LATE WED NGT.
ANY CLRG LATE WED NGT INTO THU MORN WILL BE BRIEF...SPCLY ACROSS
THE N...WITH ANOTHER S/WV DIGGING SE FROM HUDSON BAY CAN. THIS NEW
SYSTEMS WILL BRING INCREASING CLDNSS AND A CHC OF SHWRS BY LATE THU
AFTN...CONTG INTO THE EVE HRS. THIS SYSTEM WILL HAVE LESS LLVL
MOISTURE THAN TUE/WED'S SYSTEM...SO ANY RNFL FROM ISOLD TO SCT
SHWRS WILL BE LGT WITH SHWRS DISSIPATING LATE THU NGT. UNFORTUNATELY...
LEFT OVR UPPER TROFINESS OVR ERN QB LINGERING INTO FRI MAY RESULT
IN MORE SCT AFTN SHWRS ACROSS NRN/CNTRL PTNS OF THE FA FRI AFTN...
AGAIN WITH LGT RNFL AMTS. HI TEMPS ALL THREE DAYS WILL BE
COOL...WITH OVRNGT LOWS BEING TEMPERED BY CLD CVR AND A LGT GRAD
WIND.
&&
.LONG TERM /FRIDAY NIGHT THROUGH MONDAY/...
CLRG SKIES ARE XPCTD FRI NGT AS THE LAT OF THE UPPER TROF MOVES E
THRU THE CAN MARITIMES...ALLOWING SFC HI PRES TO MOVE ACROSS THE FA
FROM CNTRL CAN. THIS SHOULD ALLOW FOR GOOD RADIATIONAL COOLING
CONDITIONS LATE FRI NGT AND ERLY SAT MORN...SPCLY FOR NW VLYS...
WHERE COOLEST VLYS COULD REACH OVRNGT LOWS IN THE MID TO UPPER
30S...WITH 40S ELSEWHERE AND LOWER 50S ALG THE DOWNEAST COAST.
FOLLOWING THIS COOLEST NGT...BOTH HI AND LOW TEMPS WILL RISE A FEW
DEG EACH DAY SAT THRU MON UNDER FAIR CONDITIONS AS THE SFC HI
SLOWLY SETTLES SWRD OVR THE GULF OF ME. IN FACT HI TEMPS DUN AND
SPCLY MON WILL BREAK ABV CLIMATE NORMS.
&&
.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: PREVAILING CONDITIONS WILL BE VFR (EXCEPT FOR LOCAL IFR
DUE TO PATCHY FOG) THROUGH THE FIRST PART OF THE DAY...BUT EXPECT
LOWERING CEILINGS AS RAIN SPREADS OVER THE REGION. THE SOUTHERN
TERMINALS WILL DROP TO BELOW 3000 FT 22-24Z THIS EVENING, WHILE
ALL SITES COULD SEE OCCASIONAL MVFR VISIBILITIES THIS AFTERNOON
DUE TO RAIN AND FOG. CEILINGS WILL QUICKLY DROP TO BELOW 1000 FT
DOWNEAST AND ALONG THE COAST THIS EVENING, WHILE THE NORTHERN
TERMINALS SHOULD REMAIN MVFR THROUGH 06Z.
SHORT TO LONG TERM: HI MVFR OR LOW VFR FOR DOWNEAST TAF SITES WED
WHILE NRN/CNTRL TAF SITES CONT LOW MVFR/IFR. ALL SITES THEN
IMPROVE TO VFR OVRNGT WED AND CONT SO THRU SAT.
&&
.MARINE...
NEAR TERM: THE MAIN CONCERN ACROSS THE WATERS WILL BE REDUCED
VISIBILITY DUE TO RAIN AND FOG, ESPECIALLY THIS EVENING AND
OVERNIGHT. WINDS AND WAVES WILL STAY BELOW SMALL CRAFT CRITERIA, SO
NO HEADLINES WILL BE NEEDED.
SHORT TO LONG TERM: NO HDLNS XPCTD ATTM...BUT SRLY COMPONENT SFC
WINDS AND WVS WILL BRIEFLY INCREASE WED AHEAD OF THE LOW MOVG FROM
QUEBEC TOWARD THE GULF OF ST LAWRENCE...ENOUGH TO PERHAPS PRODUCE
UP TO 5 FT WVS OVR THE OUTERMOST WATERS LATE WED AND WED EVE.
AFTWRDS...WINDS AND WVS WILL DIMINISH LATE WED NGT THRU THE LATE
WEEK AS WIND DIRECTION BECOMES MORE OFFSHORE IN DIRECTION. WENT
WITH A BLEND OF 00Z WW3 AND SWAN NAM WV FCST DATA...SMOOTHED NEAR
THE COASTLINE TO LOWER WV HTS OVR THE INNER HARBOR/BAY WATERS BY
50 PERCENT FROM OUTER MZS.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
MARINE...NONE.
&&
$$
NEAR TERM...HASTINGS
SHORT TERM...VJN
LONG TERM...VJN
AVIATION...HASTINGS/VJN
MARINE...HASTINGS/VJN