Area Forecast Discussion
Issued by NWS Billings, MT

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FXUS65 KBYZ 262047
AFDBYZ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BILLINGS MT
247 PM MDT SUN JUL 26 2015

.SHORT TERM...VALID FOR MON AND TUE...

AN UPPER TROUGH WAS DEEPENING ALONG THE WASHINGTON/OREGON COAST
AT THE PRESENT TIME. THIS WAS DEEPENING THE SOUTHWEST FLOW OVER
THE FORECAST AREA AND INITIATING MID LEVEL HEIGHT FALLS IN THE
PROCESS. A WEAK PIECE OF ENERGY WAS KICKING ACROSS IDAHO AND
ENTERING SOUTHWEST MONTANA. THIS WAS IGNITING SOME WEAK CONVECTION
OVER WESTERN ZONES. CAPE WAS AROUND 500J/KG. EFFECTIVE BULK SHEAR
WAS 40-50KTS NORTHWEST OF BILLINGS...SO POTENTIAL IS THERE FOR AN
ISOLATED STRONG TO SEVERE STORM. ENERGY TRIGGERING THE CONVECTION
WAS WEAK...SO THINK COVERAGE SHOULD BE LIMITED SO WILL NOT MENTION
SEVERE IN THE ZONES AT THIS TIME...AS COVERAGE SHOULD BE ISOLATED.

THE MAIN FOCUS FOR THE SHORT TERM IS THE MONDAY AND TUESDAY TIME
FRAME. THE WESTERN TROUGH WILL CUT THROUGH THE AREA DURING THIS
TIME AN CUT AN UNSEASONABLY DEEP UPPER LOW OFF OVER NORTHEAST
MONTANA TUESDAY MORNING. THIS WILL DRIVE VERY STRONG ENERGY ALONG
WITH AN IMPRESSIVE COLD FRONT FOR JULY...THROUGH THE AREA MONDAY.
THE FRONT WILL PUSH INTO THE WEST IN THE MORNING...CENTRAL ZONES
LATE MORNING TO VERY EARLY AFTERNOON...AND THE EAST DURING THE
AFTERNOON AND EARLY EVENING. THE FRONT WILL HAVE STRONG PRESSURE
RISES WITH 850MB WINDS OF 40KTS. EXPECT STRONG WEST TO NORTHWEST
WINDS WITH THE FRONTAL PASSAGE AND THIS ADVERTISED WITH THE GOING
FORECAST AND WITH THE CURRENT WEATHER STORY AND OUTLOOK. WESTERN
AND CENTRAL ZONES WILL BE IN THE COOL AIR EARLY AND THUS WILL HAVE
LESS OF A FIRE WEATHER THREAT WITH THE WIND. SHOWERS AND
THUNDERSTORMS ARE LIKELY OVER WESTERN AND CENTRAL ZONES...SO
SHOULD BE A COOLER...CLOUDY AND WINDY DAY...WITH SHOWERS AND
STORMS AROUND. THE EAST WILL HAVE THE BIGGEST FIRE WEATHER THREAT
AS THIS LOCATION WILL BE MUCH WARMER WITH LOWER HUMIDITIES AHEAD
OF THE FRONT. THE FRONT WILL DRIVE THROUGH IMPRESSIVELY IN THE
AFTERNOON AND POSE A FIRE THREAT. WILL UPGRADE THE FIRE WEATHER
WATCH TO A RED FLAG WARNING FOR THE SAME LOCATIONS WITH THE SAME
TIMING.

WINDS WILL CONTINUE TO BE STRONG MONDAY NIGHT AS THE MAIN FORCING
LIFTS NORTHEAST WITH THE JET. STRONG CYCLONIC FLOW WILL TAKE OVER
FOR TUESDAY AS THE UPPER LOW MOVES INTO NORTHERN NORTH DAKOTA. A
TIGHT SURFACE PRESSURE GRADIENT AND 850MB WINDS OF 40-45KTS WILL
LEAD TO A VERY WINDY DAY FOR JULY FOR EVERYONE. STILL A QUESTION
OF HOW LOW DEWPOINTS WILL FALL AS THERE WILL BE WARP AROUND
MOISTURE TRYING TO SLIP INTO THE AREA. WILL HAVE TO MONITOR THIS
CLOSELY FOR ANOTHER POTENTIAL FIRE WEATHER DAY. HIGHS TUESDAY WILL
BE HELD IN THE 70S...WITH THE CHANCE OF PRECIPITATION CONFINED TO
NORTHERN ZONES. WINDS DECREASE TUESDAY NIGHT AS THE UPPER AND
SURFACE LOW PULLS AWAY. TWH

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

LOOKING AT A MAINLY DRY EXTENDED PERIOD WITH SLIGHTLY ABOVE
NORMAL TEMPERATURES. ENSEMBLES AND DETERMINISTIC MODELS WERE IN
GOOD AGREEMENT OVERALL. ZONAL FLOW WILL BE OVER THE REGION WITH A
DRY AIRMASS. THE GFS INTRODUCES SOME CONVECTION OVER THE AREA FRI
NIGHT DUE TO A WEAK MONSOONAL MOISTURE TAP...SO HAD A SMALL CHANCE
OF THUNDERSTORMS OVER THE MOUNTAINS. MODELS SHOWED A BACKDOOR COLD
FRONT APPROACHING THE AREA SAT NIGHT...SUPPORTING LOW CHANCES OF
MOUNTAIN CONVECTION. MOUNTAIN CHANCES OF CONVECTION WILL CONTINUE
ON SUN WITH A MONSOONAL MOISTURE TAP AND EASTERLY FLOW. ARTHUR

&&

.AVIATION...

ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS WILL AFFECT THE
REGION TONIGHT. CONDITIONS WILL BE VFR...BUT LOCALIZED MVFR CANNOT
BE RULED OUT IN ANY STRONGER THUNDERSTORMS. OTHERWISE A COLD FRONT
WILL PUSH E INTO THE AREA AFTER 06Z TONIGHT AND MOVE ACROSS THE
AREA THROUGH MON. THE FRONT WILL USHER GUSTY N TO NW SURFACE
WINDS INTO THE AREA LATE TONIGHT THROUGH MON. GUSTS UP TO 40 MPH
ARE POSSIBLE MON AFTERNOON. SHOWERS AND THUNDERSTORMS WILL BECOME
MORE NUMEROUS ACROSS THE AREA FROM W TO E DURING MON. CONDITIONS
IN THE PRECIPITATION WILL BE MVFR/IFR WITH POSSIBLE LOWER
CONDITIONS. THERE WILL BE LOCALIZED TO AREAS OF MOUNTAIN
OBSCURATION TONIGHT. MOUNTAIN OBSCURATIONS WILL INCREASE THROUGH
THE DAY ON MON. ARTHUR

&&

.PRELIMINARY POINT TEMP/POPS...

    MON     TUE     WED     THU     FRI     SAT     SUN
-----------------------------------------------------------
BIL 060/075 052/075 052/084 057/092 060/093 060/091 061/089
    26/T    42/W    11/U    00/U    01/U    11/U    11/B
LVM 055/069 047/074 047/081 051/090 053/091 055/090 055/088
    36/T    43/T    11/U    00/U    01/U    11/U    22/T
HDN 058/082 051/076 051/086 055/093 057/095 058/093 059/092
    25/T    52/W    11/U    00/U    01/U    11/U    11/B
MLS 064/087 054/072 052/085 058/093 060/094 060/092 061/090
    23/T    53/T    21/U    00/U    01/U    11/U    11/B
4BQ 062/092 053/074 051/084 056/093 060/094 060/093 061/090
    22/T    32/W    11/U    00/U    01/U    11/U    11/B
BHK 064/092 053/073 051/082 055/090 057/090 057/089 058/086
    23/T    42/T    21/U    00/U    01/U    11/U    11/B
SHR 056/084 047/072 047/081 052/091 055/092 055/090 056/088
    23/T    22/W    00/U    00/U    00/U    01/U    12/T

&&

.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...RED FLAG WARNING IN EFFECT FROM NOON MONDAY TO MIDNIGHT MDT
      MONDAY NIGHT FOR ZONES 30>33-36>38-57-58.
WY...RED FLAG WARNING IN EFFECT FROM NOON MONDAY TO MIDNIGHT MDT
      MONDAY NIGHT FOR ZONES 98-99.

&&

$$
WEATHER.GOV/BILLINGS



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