Area Forecast Discussion
Issued by NWS Billings, MT

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000
FXUS65 KBYZ 240346
AFDBYZ

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BILLINGS MT
946 PM MDT WED JUL 23 2014

.UPDATE...

STRONG UPPER LEVEL DISTURBANCE AND SURFACE LOW ARE CURRENTLY
MOVING ACROSS THE NORTHWEST PORTIONS OF THE STATE THIS EVENING.
THIS IS WHERE THE STRONGEST DYNAMICS ARE LOCATED AND THUS THE
MAJORITY OF THE SEVERE WEATHER THIS EVENING. FOR OUR FORECAST
AREA...SURFACE DEWPOINTS IN THE 50S AND 60S LATE THIS AFTERNOON
INTO THIS EVENING COMBINED WITH GOOD WIND SHEAR ALOFT WOULD
NORMALLY AID IN THUNDERSTORM DEVELOPMENT. HOWEVER...VERY WARM
TEMPERATURES ALOFT HAVE RESULTED IN A STRONG CAP ACROSS THE ENTIRE
AREA WITH NO STRONG TRIGGER MECHANISM...AS BEST DYNAMICS REMAIN
TO OUR NORTH AND NORTHWEST. THE EXCEPTION WAS ONE STRONG/SEVERE
THUNDERSTORM THAT DEVELOPED ACROSS NORTHEAST WYOMING INTO POWDER
RIVER COUNTY EARLY THIS EVENING. SPOTTERS REPORTED PEA SIZE HAIL
AND VERY HEAVY RAIN BUT QUARTER SIZE HAIL WAS REPORTED JUST
ACROSS THE BORDER INTO CAMPBELL COUNTY WYOMING. A FEW SHOWERS AND
ISOLATED THUNDERSTORMS CONTINUE IN SHERIDAN COUNTY AND OUR
SOUTHEAST COUNTIES SO HAVE ADDED A SLIGHT POP CHANCE ACROSS THESE
AREAS THROUGH 06Z. UPDATED FORECAST FOR THE REMAINDER OF THE NIGHT
HAS BEEN SENT. HOOLEY

&&

.SHORT TERM...VALID FOR THU AND FRI...

RISING HEIGHTS AND INCREASING 700 MB TEMPERATURES OVER THE
FORECAST AREA TODAY HAVE...SO FAR...HELPED TO SUPPRESS ANY
CONVECTIVE DEVELOP. THIS TREND SHOULD CONTINUE THROUGH THE
AFTERNOON. PLENTY OF SHEER AND LOW-LEVEL MOISTURE ARE IN PLACE
ACROSS EASTERN MONTANA SUCH THAT IF A STORM DID DEVELOP IT WOULD
LIKELY BECOME SEVERE...HOWEVER WE DO NOT EXPECT STORM DEVELOPMENT
WITH THE STRONG CAP IN PLACE. SO FAR...THE LACK OF A CUMULUS FIELD
IN THE VISIBLE SATELLITE SEEMS TO SUGGEST THE CAP IS HOLDING
NICELY. CONVECTIVE DEVELOPMENT IS HOWEVER EXPECTED NORTH OF THE
FORECAST AREA...FROM GREAT FALLS ACROSS TO GLASGOW ON THE NORTHERN
PERIPHERY OF THE CAP. THERE IS AN OUTSIDE CHANCE THAT SOME
THUNDERSTORMS THAT DEVELOP IN THAT AREA COULD CLIP NORTHEASTERN
FALLON COUNTY AS THE STORMS EXIT INTO THE DAKOTAS LATE THIS
EVENING.

THURSDAY REMAINS ON TRACK TO BE A HOT...DRY AND BREEZY DAY ACROSS
THE FORECAST AREA...WITH FIRE WEATHER CONCERNS NEAR-CRITICAL. THE
PACIFIC TROUGH WILL PUSH INTO SOUTHERN ALBERTA BY THURSDAY
AFTERNOON...FLATTENING OUT THE RIDGE AND FORCING A STRONG FRONT
ACROSS THE FORECAST AREA BY LATE THURSDAY AFTERNOON AND EVENING.
THIS WILL ACT TO INCREASE SOUTHWESTERLY DOWNSLOPE FLOW AHEAD OF
THE FRONT ON THURSDAY WHICH WILL HELP TEMPERATURES SURGE INTO THE
UPPER 90S TO AROUND 100 IN MANY PLACES. SOME TIMING DIFFERENCES
REMAIN IN THE FRONTAL PASSAGE...WITH THE NAM AND SREF LAYING ON
THE FAST END OF THE SPECTRUM...THE EC IN THE MIDDLE AND THE GFS ON
THE SLOW END. CURRENTLY LEANING AWAY FROM THE NAM SOLUTION...BUT
TOWARD MIDDLE GROUND OF THE EC. THIS SOLUTION GIVES THE FRONT
ARRIVING IN BILLINGS SOMETIME IN THE LATE AFTERNOON ABOUT 00Z OR
SO.

OTHER THAN THE HIGH TEMPERATURE FORECAST...THE TIMING IS ALSO
IMPORTANT FOR THE PLACEMENT OF THE CONVECTION POTENTIAL ACROSS
EASTERN MONTANA. THE FASTER PACE OF THE NAM/SREF SOLUTIONS ALLOW
THE CONVECTION DEVELOP WELL EAST...ALMOST INTO THE
DAKOTAS...WHEREAS THE SLOWER PACE OF THE EC/GFS SOLUTIONS ALLOW
FOR SCATTERED THUNDERSTORMS DEVELOPING FROM BIG HORN COUNTY WEST
ALONG THE FRONT AS IS PUSHES EASTWARD. THUS HAVE KEPT IN SLIGHT
CHANCE POPS FOR CENTRAL AND EASTERN ZONES. WOULD NOT RULE OUT THE
POTENTIAL FOR SOME OF THOSE STORMS TO BECOME STRONG TO
SEVERE ACROSS EASTERN MONTANA...SHOULD THE SLOWER FRONTAL TIME
PAN OUT.

CHURCH

.LONG TERM...VALID FOR SAT...SUN...MON...TUE...WED...

WE HAVE ABOVE-AVERAGE CONFIDENCE IN MAINLY DRY AND SEASONABLY WARM
WEATHER DURING THE UPCOMING WEEKEND AND ALL THE WAY INTO NEXT WEEK
AS RIDGING ALOFT ASSERTS ITSELF OVER THE WESTERN UNITED STATES. IT
LOOKS LIKE THE 500-MB RIDGE AXIS WILL BE MUCH FURTHER NORTHWEST OF
ITS LOCATION THIS WEEK BASED ON WELL-CLUSTERED MODEL GUIDANCE...SO
FLOW WILL BE MORE SHORTWAVE-STARVED AND THUS PROBABILITIES FOR ANY
TYPE OF CONVECTION AWAY FROM THE HIGHER TERRAIN ARE LOW. THE ECMWF
AND GFS RUNS FROM 12 UTC DO SIMULATE SOME WEAK PERTURBATIONS WHICH
COULD BATTER THE RIDGE ENOUGH TO BRING SPOTTY CONVECTION EVEN OVER
THE PLAINS BY THE EARLY AND MIDDLE PART OF NEXT WEEK...BUT THEY/RE
NOT IN AGREEMENT ON WHEN AND WHERE. WE THUS KEPT THE FORECAST OVER
MOST LOWER ELEVATIONS DRY FOR NOW. HIGHS WILL MAINLY BE IN THE 80S
F THIS WEEKEND AND RISE BACK TOWARD 90 F AGAIN NEXT WEEK. SCHULTZ

&&

.AVIATION...

ISOLATED THUNDERSTORMS WILL OCCUR OVER SE MT AND SHERIDAN COUNTY
THROUGH 06Z. EXPECT MVFR TO LIFR CONDITIONS WITH THE STORMS...WITH
LOCALIZED OBSCURATIONS OVER THE NE BIG HORNS. OTHERWISE...VFR
WILL PREVAIL OVERNIGHT. A STRONG COLD FRONT WILL PUSH SE THROUGH
THE AREA LATE TONIGHT THROUGH THU USHERING GUSTY W TO NW SURFACE
WINDS INTO THE AREA. THERE WILL BE A SLIGHT CHANCE OF AFTERNOON
THUNDERSTORMS FROM HARLOWTON TO COLUMBUS TO THE NE BIG HORNS E...
WITH MVFR TO LIFR CONDITIONS...AND LOCALIZED OBSCURATION OVER THE
NE BIG HORNS. ARTHUR
&&

.PRELIMINARY POINT TEMP/POPS...

    THU     FRI     SAT     SUN     MON     TUE     WED
-----------------------------------------------------------
BIL 066/098 057/085 057/082 056/084 059/087 061/088 061/090
    02/T    11/U    00/U    00/U    01/U    11/U    11/U
LVM 056/091 047/082 048/082 047/086 050/087 054/088 053/089
    11/N    10/N    00/U    00/U    01/U    11/B    12/T
HDN 061/101 055/086 056/083 055/085 057/089 058/090 059/091
    12/T    11/U    00/U    00/U    01/U    11/U    11/U
MLS 066/097 058/084 058/082 057/083 059/086 061/088 061/090
    22/T    21/U    11/N    00/U    00/U    11/U    11/U
4BQ 064/100 058/085 057/082 055/082 057/086 059/087 058/089
    22/T    21/U    10/U    00/U    00/U    11/U    11/U
BHK 061/096 056/083 053/079 052/079 053/082 055/084 056/086
    22/T    21/U    11/N    10/U    00/U    11/U    11/U
SHR 059/100 053/085 053/081 051/083 053/086 055/086 054/087
    22/T    11/U    10/U    00/U    01/U    11/U    11/U

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...NONE.
WY...NONE.

&&

$$
WEATHER.GOV/BILLINGS


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