Area Forecast Discussion
Issued by NWS Grand Forks, ND

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000
FXUS63 KFGF 172038
AFDFGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
338 PM CDT WED SEP 17 2014

.SHORT TERM...(THIS EVENING THROUGH THURSDAY NIGHT)
ISSUED AT 335 PM CDT WED SEP 17 2014

THE CHALLENGES FOR THE FORECAST WILL BE TEMPS AND PCPN POTENTIAL
AND PLACEMENT FOR THE END OF THE WEEK. MODELS CONTINUE TO BE IN
FAIR AGREEMENT AND USED A BLEND FOR THE FORECAST.

TONIGHT WINDS WILL TURN TO THE EAST AND SOUTHEAST AS RETURN FLOW
SETS UP BETWEEN SFC HIGH PRESSURE TRACKING ACROSS SW ONTARIO AND
DEVELOPING LOW PRESSURE ACROSS THE HIGH PLAINS. THIS SHOULD
PROVIDE ADEQUATE MIXING AND LIMIT TEMPS FOR DROPPING OFF VERY
QUICKLY...KEEPING MINS IN THE LOW 40S TO UPPER 30S.

EFFICIENT MIXING WITH TIGHTENING PRESSURE GRADIENT AND WAA WILL BE
THE MAIN THEME FOR THURSDAY. 850MB TEMPS WILL WARM INTO THE 15C TO
20C RANGE THURSDAY AFTERNOON BRINGING SFC TEMPS INTO LOW 80S IN
THE VALLEY AND WEST JUST A BIT COOLER IN THE EAST. OVERNIGHT KEPT THE
CHANCE THUNDER MOVING IN FROM THE WEST AND INTO THE NORTH WITH
SOME ELEVATED INSTABILITY HOWEVER CAPPING EXPECTED TO LIMIT
CONVECTIVE COVERAGE.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 335 PM CDT WED SEP 17 2014

FRIDAY INTO THE SATURDAY NIGHT TIME FRAME WILL BE A TRANSITION
PERIOD AS 500MB RIDGE APEX OVER THE CWFA BECOMES NW FLOW ALOFT.
SHORT WAVE ENERGY AND WEAK FROPA WILL DAMPEN THE RIDGE FRIDAY WITH
ANOTHER SHORT WAVE EXPECTED SATURDAY. WITH PWATS NEAR 1.5 INCHES
WITH 1000J/KG OF ML CAPE AND SFC TROUGH NOSING IN FROM THE WEST
WILL HAVE CHC OF SHOWERS AND THUNDERSTORMS. THAT CHANCE WILL
LINGER INTO SATURDAY WITH THE BEST MOISTURE AND INSTABILITY ACROSS
NW MN.

SATURDAY NIGHT-WEDNESDAY...MODELS IN AGREEMENT DEPICTING A
BUILDING UPPER RIDGE ALONG WITH SURFACE HIGH PRESSURE FOR MUCH OF
THIS PERIOD. THIS WILL LEAD TO MOSTLY DRY WEATHER AND TEMPERATURES
NEAR NORMAL VALUES. BIGGER QUESTIONS TOWARD THE END OF THE PERIOD
WITH AN UPPER WAVE PROPAGATING INTO THE UPPER RIDGE. THE 12Z GFS
IS SOUTH OF THE REGION WITH THIS FEATURE...AND DRY ACROSS THIS
REGION. THE 12Z ECMWF BRINGS THIS FEATURE INTO THE REGION...AND
PRODUCES PRECIP ON WEDNESDAY. KEPT THE FORECAST DRY UNTIL MORE
CONFIDENCE CAN BE OBTAINED.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1231 PM CDT WED SEP 17 2014

VFR CONDITIONS EXPECTED THROUGH THE PERIOD. MVFR CIGS NEAR THE
INTERNATIONAL BORDER (AND MOVING SOUTHWARD) ARE EXPECTED TO BREAK
APART THROUGH THE AFTERNOON HOURS. THIS SHOULD KEEP THESE CIGS JUST
NORTH OF KDVL...KGFK...AND KTVF. WILL MONITOR AND AMEND THESE TAFS
IF THE CLOUDS HOLD TOGETHER LONGER THAN ANTICIPATED (VERY LOW
PROBABILITY).


&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&

$$

SHORT TERM...JK
LONG TERM...TG/JK
AVIATION...TG







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