Area Forecast Discussion
Issued by NWS Portland, ME

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000
FXUS61 KGYX 040730
AFDGYX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAY ME
330 AM EDT TUE AUG 4 2015

.SYNOPSIS...
PERSISTENT LOW PRESSURE ALOFT...SITUATED OVER QUEBEC...WILL BRING
THE THREAT OF SHOWERS AND THUNDERSTORMS BOTH TODAY AND WEDNESDAY.
A FEW STORMS COULD BE SEVERE LATER TODAY WITH STRONG WINDS AND
LARGE HAIL...WITH ANOTHER ROUND OF STRONG STORMS POSSIBLE
WEDNESDAY AFTERNOON. COOLER AIR MOVES IN FOR THE MID TO LATE WEEK
PERIOD...AND IT WILL BE MAINLY DRY...ALTHOUGH SCATTERED SHOWERS
WILL BE POSSIBLE IN THE MOUNTAINS THURSDAY. FRIDAY LOOKS MOSTLY
DRY FOR NOW. THERE IS CHANCE FOR SOME RAIN OVER THE WEEKEND AS LOW
PRESSURE JUST OFF THE COAST.

&&

.NEAR TERM /THROUGH TODAY/...
AT 06Z...A PREFRONTAL TROUGH WAS DRAPED ACROSS THE FORECAST AREA
WITH A COLD FRONT OVER THE EASTERN GREAT LAKES. FOR TODAY...THE
FRONT WILL INCH EASTWARD WITH CONVECTION INCREASING IN COVERAGE
WITH DAYTIME HEATING AND APPROACH OF UPPER IMPULSE AND ASSOCIATED
SURFACE COLD FRONT. MODIFIED BUFKIT FORECAST SOUNDINGS FROM
NAM/GFS YIELD CAPES NEAR 2000 J/KG AND MODERATE SHEAR. EXPECT
ORGANIZED STORMS AND LINE SEGMENTS ONCE AGAIN TODAY WITH DAMAGING
WINDS AND LARGE HAIL THE PRIMARY THREATS. HIGHS WILL RANGE FROM
70S IN THE MOUNTAINS TO THE 80S ELSEWHERE.

&&

.SHORT TERM /TONIGHT THROUGH 6 PM WEDNESDAY/...
THE COLD FRONT WILL CLEAR THE AREA OVERNIGHT...BRINGING COOLER
AND DRIER AIR BACK TO THE REGION. WITH LOWS IN THE 50S AND LOWER
60S. WEDNESDAY WILL PROVE TO BE ANOTHER INTERESTING DAY AS COOL
CYCLONIC FLOW..DAYTIME HEATING AND PASSING IMPULSE PRODUCE ANOTHER
ROUND OF CONVECTION WITH POTENTIAL FOR SMALL HAIL AND GUSTY WINDS.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
HIGH IMPACT WEATHER: NONE.

500 MB PATTERN STARTS WITH STRENGTHENING RIDGES OVER THE SRN CONUS
AND MEAN TOUGHING IN THE NERN US. WHILE THERE IS SOME FLATTENING
OF THE TROUGH TOWARD THE END OF THE WEEK...THE GENERAL TREND IS
FOR THE TROUGH TO HOLD TO SOME DEGREE THRU EARLY NEXT WEEK. THIS
PATTERN WOULD KEEP THE HOT AIR TO OUT WEST BUT SURPRISINGLY THE
AIR IN THE TROUGH IS NOT ALL COOL. THIS WOULD KEEP TEMPS NEAR
NORMAL WITH UNSETTLED CONDITIONS.

SPECIFICALLY...WED NIGHT SHOULD FEATURE A SECONDARY PUSH OF THE
COOLER AND DRIER SFC AIR IN NW FLOW...WITH PERHAPS A FEW SHRA IN
THE MTNS. THU AND FRI LOOK MAINLY DRY AS WEAK SFC HIGH BUILDS IN
BENEATH NEARLY ZONAL FLOW ALOFT. THE FORECAST BECOMES MUCH MORE
MUDDLED FOR THE WEEKEND AS THE 00Z MEDIUM RANGE MODELS SHOW QUITE
DIVERGENT SOLNS...WHICH RANGE FROM THE GEMS COMPLETE MISS OF A
COASTAL LOW WELL TO THE SOUTH...TO THE EUROS WINTER-LIKE COASTAL
BOMB. NOT MUCH CONFIDENCE IN THE FORECAST BEYOND FRIDAY AT THIS
POINT. GIVEN THAT ALL MODELS LOOK TO BE DEALING WITH CONVECTIVE SCALING
ISSUES AND AT TIMES DO NOT MAKE METEOROLOGICAL SENSE...HAVE OPTED
TO GO WITH JUST CHC POPS SAT-SUN...WITH THE BEST CHC SAT
NIGHT...AS THIS IS CLOSEST TO WHAT MIGHT CALLED MODEL
CONSENSUS...AND AGREES WITH SUPERBLEND. SEE WPC EXTENDED FORECAST
DISCUSSION /PMDEPD/ FOR A GOOD EXPLANATION OF THE MODEL ISSUES
WITH THIS SYSTEM. STILL...ONE THING TO TAKE HOME ABOUT THE MODELS
IN THE MEDIUM TO LONG RANGE IS THAT THEY ARE PROBABLY PICKING UP
ON SOMETHING...BUT HOW THAT PANS OUT AND WHAT ITS IMPACTS WILL BE
NEED TO BEEN FROM A SHORTER TIMEFRAME THAN DAYS 5 AND 6.

TEMPERATURES THU AND FRI WILL SEE HIGHS IN THE LOW 70S NORTH TO
AROUND 80 IN INTERIOR SW ME AND SRN NH...WITH OVERNIGHT MOSTLY IN
THE 50S. DEPENDING ON HOW THE SYSTEM OVER THE WEEKEND
PLAYS...AND ASSUMING IT AMOUNTS MORE TO SHOWERS AND SOME COOLER
N-NE FLOW...DAYTIME HIGHS WILL BE IN THE 70S AND OVERNIGHT LOWS IN
THE MID 50S TO LOW 60S. SHOULD SEE AT LEAST SLIGHT WARM UP EARLY
NEXT WEEK.

&&

.AVIATION /07Z TUESDAY THROUGH SATURDAY/...
SHORT TERM /THROUGH WED/ ... AREAS OF MVFR IN SHRA/TSRA WITH LCL
IFR PSBL IN +TSRA ALONG WITH STRONG WIND GUSTS AND LARGE HAIL
THROUGH 02Z. AREAS OF STRATUS AND FOG WITH LCL IFR TONIGHT. AREAS
OF MVFR WED IN SHRA/TSRA.

LONG TERM...MAINLY VFR THURSDAY THROUGH SATURDAY...ALTHOUGH HIGH
PROBABILITY OF VLY FOG AT KHIE/KLEB WED AND THU NIGHT.

&&

.MARINE...
SHORT TERM...PERSISTENT SSW FLOW AHEAD OF SLOWLY APPROACHING COLD
FRONT WILL KEEP WINDS AND SEAS JUST BELOW SCA THRESHOLDS THRU
THIS EVENING. SCA WAS DROPPED WITH NEW MARINE PACKAGE THIS
MORNING.

LONG TERM...THU AND FRI WILL SEE CONDS COMFORTABLY BELOW SCA
LVLS. DEPENDING ON TRACK OF LOW PRESSURE THIS WEEKEND COULD SEE
A PERIOD OF SCA WINDS SEAS OVER THE WEEKEND.

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...NONE.
NH...NONE.
MARINE...NONE.

&&

$$
SCHWIBS/CEMPA


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