Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 030421
AFDFGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
1121 PM CDT SAT MAY 2 2015

.UPDATE...
ISSUED AT 1120 PM CDT SAT MAY 2 2015

NO CHANGES NEEDED WITH THIS UPDATE.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 305 PM CDT SAT MAY 2 2015

FORECAST CHALLENGE CONCERNS NEAR TERM PCPN CHANCES...FIRE WEATHER
CONCERNS TOMORROW AND TEMPERATURES. MODELS IN REASONABLE AGREEMENT
THROUGH THE PERIOD AND WILL USE BLEND FOR FORECAST.

BEGINNING TO SEE SOME LTG STRIKES VCNTY DVL AREA WITH RADAR
RETURNS APPROACHING FROM THE WEST AHEAD OF BOUNDARY. MOISTURE
LOOKS TO BE THE MAIN INHIBITOR WITH THIS BAND. PRECIPITABLE H2O
VALUES BARELY OVER A HALF INCH ALONG WITH A NARROW BAND OF JUST MID
40 DEWPOINTS. MODEL SOUNDINGS INDICATING VERY DRY LAYER BLO 700 MB
SO QUESTION HOW MUCH PCPN REACHING THE GROUND. FOR THIS WILL JUST
KEEP CHC POPS GOING THIS EVENING AS THINK ANY CONVECTION WILL BE
VERY SPOTTY. THERE IS SOME WEAK CAPE AND MINOR INSTABILITY ALONG
WITH SUFFICIENT DOWNWARD CAPE SO IF ANY THING DOES GET SOMEWHAT
ORGANIZED GUSTY WINDS WILL BE THE PRIMARY THREAT. NEGATIVE SHOWALTERS
PERSIST OVERNIGHT HOWEVER LOW LEVEL JET LACKING SO CONVECTION WILL
BE PRIMARILY DIURNAL IN NATURE. COLD ADVECTION WORKS IN MAINLY AFT
MIDNIGHT HOWEVER WITH WARM DAY MINIMUMS SHOULD STILL RANGE ABOVE
AVERAGE.

LOW CONFIDENCE ON HOW LONG SHOWERS WILL LINGER OVER THE FAR SE
TOMORROW AM HOWEVER MAINTAINED SOME VERY LOW POPS. FIRE WEATHER
CONCERNS CONTINUE TOMORROW. RH VALUES WILL BE LOW HOWEVER
TEMPERATURES WILL BE COOLER AND ALL GUIDANCE KEEPING WIND SPEEDS
BLO DANGEROUS LEVELS. SEE DETAILS IN FIRE WEATHER SECTION OF THE
DISCUSSION. TEMPERATURES WILL BE MUCH CLOSER TO AVERAGE AS COOLER
AIRMASS MOVES IN.

HIGH PRESSURE MOVES IN SUNDAY NIGHT. WITH DIMINISHING WIND...DRY
AIRMASS AND COOLER COLUMN TEMPERATURES SHOULD DROP TO AROUND 40
MOST AREAS.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 305 PM CDT SAT MAY 2 2015

HIGH PRESSURE IN PLACE MONDAY FOR QUIET DAY. COOLER AIRMASS IN
PLACE THAN PAST SEVERAL DAYS BUT STILL SHOULD SEE VALUES AT OR A
BIT ABOVE AVERAGE.

E-W BOUNDARY SETS UP ACROSS THE CENTRAL PLAINS TUESDAY AS UPPER
LOW PROPAGATES INTO THE 4 CORNERS AREAS HOWEVER AT THIS POINT ANY
RELATED CONVECTION LOOKS TO STAY SOUTH OF THE FA SO KEPT FORECAST
DRY.

CONFIDENCE GROWING THAT PATTERN SHOULD TURN BOTH ACTIVE AND WET.
WITH AN H5 TROF DEEPENING INTO THE WESTERN CONUS...SITUATION SHOULD
BE SET FOR PERIOD SOUTHWESTERLY FLOW ALOFT...WITH LOW LEVEL MOISTURE
TRANSPORT...AND DEEP LAYER INSTABILITY ACROSS THE NORTHERN PLAINS
LATE WEDNESDAY. BOTH THE GFS AND ECMWF KEEP THE H5 TROF ANCHORED
BACK OF RENO WITH SUCCESSIVE H5 SHORTWAVES LIFTING THROUGH THE
NORTHERN PLAINS FRIDAY AND SATURDAY...AND A SLIGHT EASTWARD SHIFT IN
THE H5 TROF AXIS INTO FOLLOWING WEEK. THE LATE WEEK PERIOD SHOULD
TRANSITION INTO A COOLER /MORE SEASONABLY MILD/ REGIME AS OVERALL
HEIGHTS LOWER AND PREDOMINATELY NORTHERLY BLAYER FLOW IS ESTABLISHED
THU-SAT.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1120 PM CDT SAT MAY 2 2015

VFR CONDITIONS EXPECTED WITH SHOWERS AND STORMS MOVING EAST OF THE
AREA. THE MAIN CHALLENGE LATER TONIGHT WILL BE IF THERE IS ANY FOG
FORMATION LATER TONIGHT. WITH DRIER NW FLOW MOVING IN BEHIND THE
FRONT...WILL NOT MENTION FOG...BUT THREAT IS POSSIBLE MAINLY IN
THE EAST NEAR THE SFC BOUNDARY LATER TONIGHT INTO EARLY SUNDAY MORNING.

&&

.FIRE WEATHER...
ISSUED AT 337 AM PM CDT SAT MAY 2 2015

SOUTHERLY WINDS AT 20 TO 25 MPH WITH GUSTS TO 35 MPH WILL CONTINUE
FOR THE BALANCE OF THE AFTERNOON. THESE WINDS ARE ACCOMPANIED BY
HUMIDITY VALUES ALREADY NEAR 15 PERCENT OVER THE NORTHERN
VALLEY...SO CRITICAL FIRE CONDITIONS HAVE BEEN ATTAINED. TURNING THE
ATTENTION TO SUNDAY...FEEL THAT HUMIDITY WILL BE 5 TO 10 PERCENT
HIGHER ON AVERAGE LARGELY ATTRIBUTED TO THE SOMEWHAT COOLER AIR MASS
THAT WILL BE IN PLACE. IT WILL BE BREEZY BUT LOOKS LIKE SUSTAINED
WINDS FROM THE NORTHWEST WILL TOP OUT AT OR AROUND 20 MPH OVER
MOST OF THE REGION...A LITTLE LESS EAST OF THE VALLEY. THEREFORE NOT
PLANNING A FIRE WEATHER WATCH FOR TOMORROW...WILL MENTION NEAR
CRITICAL CONDITIONS IN THE FIRE WEATHER PLANNING FORECAST.

&&

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

$$

UPDATE...DK
SHORT TERM...VOELKER
LONG TERM...GUST/VOELKER
AVIATION...DK
FIRE WEATHER...WJB





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