524
FXUS65 KTFX 010005
AFDTFX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREAT FALLS MT
600 PM MDT SUN MAY 31 2020
..UPDATED AVIATION SECTION AND NEAR TERM UPDATE
SYNOPSIS
A PASSING COLD FRONT HAS LEFT GUSTY WESTERLY WINDS BUT DRIER
CONDITIONS IN ITS WAKE. THE WINDS ARE EXPECTED TO DIMINISH THIS
EVENING. ANOTHER ROUND OF SHOWERS AND SOME THUNDERSTORMS ARE
EXPECTED OVER THE CENTRAL AND SOUTHWEST FOR MONDAY AFTERNOON AND
EVENING. BREEZY AND DRIER CONDTIONS ARE THEN EXPECTED THROUGH LATE
WEEK FOR MOST AREAS.
DISCUSSION
600 PM UPDATE...WESTERLY WINDS, THOUGH STILL FAIRLY STRONG, ARE
DECREASING SOMEWHAT OVER THE ROCKY MOUNTAIN FRONT AND OUT ONTO THE
ADJACENT PLAINS. THE WINDS SHOULD GENERALLY REMAIN BELOW HIGH WIND
CRITERIA THROUGH THE EVENING AS THEY CONTINUE TO DECREASE, SO HAVE
ALLOWED THE HIGH WIND WARNING FOR THAT AREA TO EXPIRE. COULSTON
REMAINDER OF THIS AFTERNOON THROUGH MONDAY NIGHT...A PACIFIC COLD
FRONT HAS JUST CLEARED THE FAR EASTERN PORTIONS OF THE CWA, LEAVING
GUSTY WINDS AND MILD, DRIER CONDITIONS IN ITS WAKE. HOWEVER, THERE
ARE A FEW LEFT OVER ISOLATED SHOWERS ALONG THE DIVIDE. THE STRONG
WINDS THAT BROUGHT BLOWING DUST IN SOME AREAS HAVE DIMINISHED
SOMEWHAT BUT ARE STILL ON THE STRONGER SIDE, ESPECIALLY ALONG THE
ROCKY MOUNTAIN FRONT AND THE ADJOINING PLAINS. WILL KEEP THE HIGH
WIND WARNING GOING THROUGH THE 0Z EXPIRATION AS THERE IS STILL A
CHANCE OF 50 KT H700 WINDS MIXING DOWN TO THE SURFACE IN THESE
AREAS. TONIGHT WINDS ARE EXPECTED TO DIMINISH AS SHORTWAVE RIDGING
BRIEFLY PASSES THROUGH THE REGION. LOW TEMPERATURES WILL BE MUCH
COOLER COMPARED TO LAST NIGHT BUT WILL STILL BE NEAR OR ABOVE THE
SEASONAL AVERAGE FOR MOST LOCATIONS. MONDAY WILL BEGIN DRY BUT
ANOTHER DISTURBANCE WILL DISPLACE THE AFOREMENTIONED SHORTWAVE
RIDGING AND WILL BRING SOME SHOWERS AND THUNDERSTORMS TO CENTRAL AND
SOUTHWESTERN AREAS BY MONDAY AFTERNOON. SEVERE STORMS ARE NOT
EXPECTED AT THIS TIME BUT A FEW CAN BE ON THE STRONG SIDE WITH GUSTY
WINDS AND SMALL HAIL SINCE THERE WILL BE SOME UPPER LEVEL SUPPORT
AND INSTABILITY WITH THIS SYSTEM. BY MONDAY NIGHT, THIS ACTIVITY IN
MOVE NORTHEASTWARD TOWARD THE EASTERN PORTIONS ON CENTRAL/NORTH-
CENTRAL MONTANA WHILE WEAKENING AND EVENTUALLY MOVING OUT OF THE
AREA. RCG
TUESDAY THROUGH SUNDAY...WESTERLY FLOW WILL THEN TAKE SHAPE
THROUGH THURSDAY, BRINGING MORE THE WESTERLY WINDS AND MOSTLY DRY
CONDITIONS. THEN, A BROAD LOW PRESSURE TROUGH IS EXPECTED TO BRING
A MORE CYCLONIC WESTERLY TO SOUTHWESTERLY FLOW ALOFT INTO NEXT
WEEKEND. ALTHOUGH THIS WILL LIKELY NOT IMPACT TEMPERATURES
SIGNIFICANTLY (STILL LOOKING AT TEMPERATURES AROUND 5 TO 10
DEGREES ABOVE NORMAL), THE GREATER IMPACT WILL BE AN INCREASE IN
THE CHANCE FOR SHOWERS AND THUNDERSTORMS ACROSS MUCH OF NORTH-
CENTRAL AND SOUTHWEST MONTANA. RCG/CC
AVIATION
UPDATED 600 PM MDT SUN MAY 31 2020 (01/00Z-02/00Z TAF ISSUANCE)
VFR CONDITIONS WILL CONTINUE OVER MUCH OF THE FORECAST AREA THROUGH
AT LEAST THE NEXT 24 HOURS. LINGERING MOUNTAIN TOP OBSCURING SHOWERS
ON THE ROCKY MOUNTAIN FRONT WILL DECREASE THROUGH 06Z. MOST OF THE
AREA WILL REMAIN MOSTLY CLEAR FOR MUCH OF THE PERIOD, AS THE STRONG
WESTERLY WINDS GUSTING BETWEEN 35 AND 45 KT DECREASE THROUGH 06Z.
HOWEVER, A DISTURBANCE WILL SPREAD HIGH AND MID LEVEL CLOUDINESS
INTO SOUTHWEST MONTANA AFTER 06Z AND OVER CENTRAL AND NORTH CENTRAL
MONTANA THROUGH THE REMAINDER OF THE PERIOD. THIS DISTURBANCE MAY
ALSO BRING SCATTERED SHOWERS AND THUNDERSTORMS TO PORTIONS OF
SOUTHWEST MONTANA AFTER 18Z, POSSIBLY CAUSING PERIODS OF MVFR
CONDITIONS. COULSTON
NOTE: AMENDMENTS NOT SCHEDULED FOR ENNIS (KEKS) DUE TO ONGOING
RUNWAY CLOSURE.
HYDROLOGY
THERE HAVE BEEN WATER LEVEL RISES ON BADGER CREEK BELOW FOUR
HORNS CANAL NEAR BROWNING, AND THE SAINT MARY RIVER AT
INTERNATIONAL BOUNDARY. A FLOOD ADVISORY HAS BEEN ISSUED FOR THE
AREAS ALONG BADGER CREEK BELOW FOUR HORNS CANAL NEAR BROWNING
THROUGH MONDAY AFTERNOON.
PRELIMINARY POINT TEMPS/POPS
GTF 46 76 47 76 / 0 0 30 0
CTB 45 72 44 73 / 0 0 10 0
HLN 48 79 48 78 / 0 20 40 10
BZN 46 82 50 77 / 0 20 40 20
WYS 41 76 43 70 / 0 0 20 30
DLN 46 78 48 76 / 0 30 20 20
HVR 48 79 50 78 / 0 0 30 0
LWT 48 75 48 72 / 0 10 60 10
TFX WATCHES/WARNINGS/ADVISORIES
NONE
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