Special Weather Statement, NWS Billings, MT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
248 PM MDT MON JUL 21 2014

.SHORT TERM...VALID FOR TUE AND WED...

THE MAIN MESSAGE IN THE SHORT TERM FORECAST REMAINS UNCHANGED
TODAY. SOME ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE
EXPECTED ACROSS THE AREA TUESDAY AND WEDNESDAY. THE BETTER CHANCE
FOR ANY STRONG THUNDERSTORMS IS ON WEDNESDAY...ALTHOUGH
CONFIDENCE IN COVERAGE REMAINS LOW.

THIS MORNING\S SHORTWAVE HAS EXITED INTO NORTH DAKOTA WHERE AN MCS
IS STARTING TO DEVELOP. SUBSIDENCE OVER SOUTHEAST MONTANA BEHIND
THE WAVE HAS ALLOWED SKIES TO CLEAR OUT. THE SECONDARY WAVE IS
NOW MOVING INTO SOUTHWEST MONTANA...WITH CONVECTION STARTING TO
DEVELOP OVER THE SOUTHWEST MOUNTAINS. THIS WAVE WILL PUSH ACROSS
THE FORECAST AREA THROUGH THIS EVENING. DEW POINTS REMAIN IN THE
MID 50S TO LOW 60S FOR CENTRAL AND WESTERN ZONES...WITH
MESOANALYSIS SUGGESTING SOME MODEST INSTABILITY OF 500 TO 1000
J/KG. EXPECT TO SEEM SOME ISOLATED STRONGER STORMS DEVELOP IN THE
INCREASING SHOWER AND THUNDERSTORM ACTIVITY. THE CLEAR SKIES
ACROSS THE SOUTHEAST SHOULD SUPPORT BETTER DESTABILIZATION THROUGH
THIS AFTERNOON BEFORE THE WAVE APPROACHES. THIS IS THE AREA WHERE
WE ARE MOST CONCERNED FOR STRONGER WIND GUSTS WITH ANY
THUNDERSTORMS THAT DEVELOP. HIGH RESOLUTION MODELS FURTHER CONFIRM
THIS THINKING. AN ISOLATED SEVERE WIND REPORT CANNOT BE RULED
OUT...HOWEVER...WE EXPECTED WINDS TO REMAIN SUB-SEVERE ON THE
WHOLE.

TUESDAY WILL BE MAINLY DRY AND WARMER AS THE RIDGE AXIS BUILD INTO
THE FORECAST AREA. THE RISING HEIGHT WILL RESULT IN SOME WEAK
SUBSIDENCE...WHICH SHOULD BE ENOUGH SUPPRESS MOST CONVECTION IN
CENTRAL ZONES. THAT SAID...WOULD NOT RULE OUT SOME ISOLATE SHOWERS
AND THUNDERSTORMS AROUND PERIPHERY OF THE RIDGE AXIS...AND EAST
OF THE SURFACE TROUGH ACROSS SOUTHEAST MONTANA. THE BETTER CHANCE
FOR THUNDERSTORMS LOOKS TO BE WEDNESDAY...HOWEVER NOT EXPECTING A
WIDESPREAD EVENT. THE TWO LOCATIONS OF INTEREST WILL BE 1/
NORTHWEST OF THE FORECAST AREA FROM MISSOULA TO GREAT FALLS WHERE
THE BETTER FORCING EXISTS FROM THE PACIFIC WAVE AND 2/ ACROSS FAR
EASTERN MONTANA ON THE EAST SIDE OF THE SURFACE TROUGH. THOSE
LOCATIONS WILL ALSO SEE THE BEST CHANCE OF SEVERE WEATHER AS THE
MODEST INSTABILITY WILL COMBINE WITH IMPRESSIVE DEEP LAYER SHEER.
OVERALL NOT EXPECTING MOST AREAS WILL SEE MUCH IN THE WAY OF
SIGNIFICANT PRECIPITATION...WHICH COMBINED WITH HOT TEMPERATURES
WILL CONTINUE TO DRY OUT THE FIRE WEATHER FUELS ACROSS THE AREA.

CHURCH

.LONG TERM...VALID FOR THU...FRI...SAT...SUN...MON...

CRITICAL FIRE WEATHER CONDITIONS ARE A DISTINCT POSSIBILITY ACROSS
THE LOWER ELEVATIONS OF SOUTHERN MT AND PERHAPS SHERIDAN COUNTY WY
ON THURSDAY AND THURSDAY EVENING. MODEL GUIDANCE CONTINUES SHOWING
A RELATIVELY CLASSIC BREAKDOWN OF THE UPPER-LEVEL RIDGE...WITH THE
12 UTC GFS HOLDING WARMER AIR ALOFT IN PLACE OVER MORE OF THE AREA
LONGER DURING THE DAY THURSDAY AHEAD OF AN APPROACHING COLD FRONT.
FORECAST SOUNDINGS FROM THE 12 UTC GFS SIMULATE VERTICAL MIXING TO
ALMOST 500 MB OVER THE PLAINS...WHICH COULD PUSH HIGHS TO 100 F IN
SOME PLACES LIKE BILLINGS...MILES CITY AND SHERIDAN IF THE FRONTAL
PASSAGE DOES INDEED OCCUR WITH A GFS-LIKE TIMING. GUSTY WINDS WITH
LOW HUMIDITIES ARE ALSO EXPECTED IN THAT SCENARIO...SO WE MAY NEED
TO ISSUE A FIRE WEATHER WATCH FOR PARTS OF THE AREA IN THE NEXT 24
HOURS.

IN THE WAKE OF THE SHORTWAVE TROUGH THAT BREAKS DOWN THE RIDGE...A
DRY NORTHWEST FLOW ALOFT WILL BE IN PLACE FOR THE WEEKEND...BEFORE
500-MB RIDGING BUILDS BACK NORTHWARD BY EARLY NEXT WEEK. HIGHS MAY
BE SOMEWHAT COOLER /IN THE 80S F/ THIS WEEKEND BEFORE WARMING BACK
UP INTO THE 90S F BY EARLY NEXT WEEK OVER THE PLAINS. WE LEANED ON
CONTINUITY AND THE MULTI-MODEL CONSENSUS FOR THE FORECAST...BUT AS
VEGETATION AND SOIL MOISTURE CONTINUES TO SLOWLY DRY OUT THIS WEEK
IT/S POSSIBLE HIGHS WILL END UP A BIT WARMER THAN WE ARE CURRENTLY
ADVERTISING. SCHULTZ

&&

.AVIATION...

SCATTERED SHOWERS AND THUNDERSTORMS WITH LOCAL MVFR CONDITIONS ARE
EXPECTED ACROSS SOUTHERN MT AND NORTH CENTRAL WY THROUGH THE EARLY
EVENING HOURS. A FEW STORMS MAY BE STRONG WITH GUSTY WINDS...HEAVY
RAINFALL AND A SMALL RISK OF LOCAL/BRIEF IFR CONDITIONS. WE EXPECT
THE ACTIVITY TO DIMINISH BY MID TO LATE EVENING AND VFR CONDITIONS
WILL THEN PREVAIL OVERNIGHT AND ON TUESDAY. SCHULTZ

&&

.PRELIMINARY POINT TEMP/POPS...

    TUE     WED     THU     FRI     SAT     SUN     MON
-----------------------------------------------------------
BIL 061/090 063/095 064/096 058/084 057/085 058/086 059/090
    31/B    12/T    21/N    11/U    11/U    11/U    11/U
LVM 054/089 055/093 055/088 050/083 049/083 049/088 051/090
    52/T    22/T    21/N    11/U    11/U    11/U    11/U
HDN 059/092 060/099 061/097 057/086 056/086 057/088 058/091
    31/B    12/T    21/U    11/U    11/U    11/U    11/U
MLS 063/090 065/095 066/097 059/085 058/085 059/086 059/088
    42/T    22/T    21/U    11/U    11/N    11/U    11/U
4BQ 061/090 062/097 064/097 059/085 058/085 058/085 058/088
    32/T    12/T    21/U    11/U    11/U    11/U    11/U
BHK 058/086 060/090 061/092 057/083 053/083 054/083 054/084
    43/T    22/T    22/T    21/U    11/N    11/U    11/U
SHR 055/090 058/096 058/096 054/084 053/084 053/085 054/087
    31/B    12/T    21/U    11/U    11/U    11/U    11/U

&&

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

&&

WEATHER.GOV/BILLINGS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BILLINGS MT
313 PM MDT MON JUL 21 2014

MTZ028>042-056>058-063>068-WYZ098-099-222115-
SOUTHERN WHEATLAND-MUSSELSHELL-TREASURE-NORTHERN ROSEBUD-CUSTER-
FALLON-NORTHERN STILLWATER-YELLOWSTONE-POWDER RIVER-CARTER-
SOUTHERN BIG HORN-EASTERN CARBON-NORTHERN PARK-
NORTHERN SWEET GRASS-GOLDEN VALLEY-RED LODGE FOOTHILLS-
NORTHERN BIG HORN-SOUTHERN ROSEBUD-JUDITH GAP-PARADISE VALLEY-
LIVINGSTON AREA-BEARTOOTH FOOTHILLS-ABSAROKA/BEARTOOTH MOUNTAINS-
CRAZY MOUNTAINS-NORTHEAST BIG HORN MOUNTAINS-SHERIDAN FOOTHILLS-
313 PM MDT MON JUL 21 2014

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL
MONTANA...SOUTH CENTRAL MONTANA...SOUTHEAST MONTANA AND NORTH
CENTRAL WYOMING.

.DAY ONE...TONIGHT

SCATTERED STRONG THUNDERSTORMS WILL CONTINUE ACROSS THE AREA THIS
THROUGH THIS EVENING. THE MAIN THREAT WITH THESE STORMS IS STRONG
WIND GUSTS...HEAVY RAINFALL AND FREQUENT LIGHTNING.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

FIRE WEATHER CONCERNS INCREASE ON THURSDAY. HOT AND DRY WEATHER
WILL CONTINUE LEADING UP TO THURSDAY...FURTHER DRYING OUT FUELS
ACROSS THE AREA. A STRONG COLD FRONT WILL MOVE ACROSS THE AREA
THURSDAY AFTERNOON...RESULTING IN GUSTY WINDS WHICH WILL INCREASE
THE FIRE WEATHER DANGER. BE ALERT TO THE INCREASING FIRE DANGER
AND TAKE ACTIONS TO MITIGATE THE CHANCE OF STARTING A FIRE.

A FEW STRONG TO SEVERE THUNDERSTORMS ARE POSSIBLE WEDNESDAY
AFTERNOON AND EVENING ACROSS NORTHERN MONTANA...AS WELL AS FAR
EASTERN MONTANA.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BILLINGS MT
510 PM MDT MON JUL 21 2014

MTZ029-034-035-042-212345-
MUSSELSHELL MT-NORTHERN STILLWATER MT-YELLOWSTONE MT-
GOLDEN VALLEY MT-
510 PM MDT MON JUL 21 2014

...SIGNIFICANT WEATHER ADVISORY...

AT 503 PM MDT...DOPPLER RADAR WAS TRACKING AN AREA OF THUNDERSTORMS
ACROSS SOUTHEAST GOLDEN VALLEY COUNTY MOVING NORTHEAST AT 30 MPH.
BRIEF HEAVY RAIN ALONG WITH SMALL HAIL CAN BE EXPECTED WITH THESE
THUNDERSTORMS. AN AREA OF OUTFLOW WINDS OF 40 TO 50 MPH AHEAD OF THE
THUNDERSTORMS WILL MOVE SOUTHEAST INTO SOUTHERN
MUSSELSHELL...NORTHEAST STILLWATER AND NORTHWEST YELLOWSTONE COUNTY
DURING THE NEXT HALF HOUR.

LOCATIONS IMPACTED INCLUDE...
BROADVIEW...LAVINA...MOLT...CUSHMAN...BELMONT...ACTON AND COMANCHE.

LAT...LON 4583 10896 4630 10915 4640 10878 4632 10857
      4594 10849
TIME...MOT...LOC 2303Z 240DEG 35KT 4628 10897

HOOLEY

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BILLINGS MT
541 PM MDT MON JUL 21 2014

MTZ038-057-220030-
NORTHERN BIG HORN MT-SOUTHERN BIG HORN MT-
541 PM MDT MON JUL 21 2014

...SIGNIFICANT WEATHER ADVISORY...

AT 538 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 14
MILES NORTHEAST OF FORT SMITH...OR 19 MILES SOUTH OF HARDIN...MOVING
NORTHEAST AT 30 MPH. BRIEF HEAVY RAIN ALONG WITH SMALL HAIL WILL BE
LIKELY WITH THIS THUNDERSTORM. WINDS GUSTING 40 TO 50 MPH WILL BE
POSSIBLE AHEAD OF THIS STORM AS WELL.

LOCATIONS IMPACTED INCLUDE...
ST. XAVIER.

LAT...LON 4530 10783 4550 10792 4559 10768 4535 10745
TIME...MOT...LOC 2338Z 240DEG 35KT 4547 10775

HOOLEY

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BILLINGS MT
721 PM MDT MON JUL 21 2014

WYZ099-220200-
SHERIDAN FOOTHILLS WY-
721 PM MDT MON JUL 21 2014

...SIGNIFICANT WEATHER ADVISORY...

AT 718 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM
NEAR SHERIDAN...MOVING NORTHEAST AT 40 MPH. BRIEF HEAVY RAIN...SMALL
HAIL AND GUSTY WINDS AROUND 40 MPH WILL BE LIKELY WITH THIS
THUNDERSTORM.

LOCATIONS IMPACTED INCLUDE...
SHERIDAN...BIG HORN AND WYARNO.

LAT...LON 4462 10694 4483 10701 4490 10663 4471 10653
TIME...MOT...LOC 0118Z 255DEG 39KT 4474 10687

HOOLEY