997
FXUS65 KCYS 201134
AFDCYS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
534 AM MDT SUN OCT 20 2019
SHORT TERM
(TODAY THROUGH TUESDAY)
ISSUED AT 300 AM MDT SUN OCT 20 2019
LOTS GOING ON THIS MORNING WITH STRONG WINDS AND SNOW THE PRIMARY
FORECAST CHALLENGES WITH THIS FORECAST PACKAGE.
CURRENTLY...IR IMAGERY SHOWING A FAIRLY STRONG LOW PRESSURE
SYSTEM IN THE VICINITY OF WORLAND TO RIVERTON THIS MORNING. COLD
FRONT ASSOCIATED WITH THE LOW EXTENDS SOUTH ALONG THE LARAMIE
RANGE THIS MORNING. SEEING COOLING CLOUD TOPS ON IR IMAGERY AS A
90+ KT JET FINGER BEGINS TO MOVE INTO NORTHWEST COLORADO AND
SOUTHWESTERN CARBON COUNTY. WE HAVE SEEN A LITTLE BREAK IN THE
SNOW OUT WEST EARLY THIS MORNING...BUT WITH THE COOLING CLOUD
TOPS...WOULD EXPECT SNOW TO RETURN TO MUCH OF CARBON COUNTY OVER
THE NEXT COUPLE HOURS.
WINDS HAVE BEEN ON THE INCREASE BEHIND THE FRONT. COOPER COVE JUST
HIT 58 MPH ON THEIR GUSTS. THE OTHER WYDOT SITES IN ZONE 114 ARE
BEGINNING TO COME UP AS WELL...SO DO FEEL THE WIND EVENT IS GOING
TO OCCUR. LATEST GFS HIGH WIND GUIDANCE SHOWING CRAIG TO CASPER
850/700MB HEIGHT GRADIENTS INCREASING TO 76/71 MTRS BY 09Z AND
90/87MTRS BY 12Z. SO WILL NOT CHANGE ANY WIND HEADLINES FOR TODAY.
DID ADD A SNOW ADVISORY TO CONVERSE AND NIOBRARA COUNTY STARTING
AT 12Z. WRAP AROUND MOISTURE FROM THE LOW LOOKS TO TRACK RIGHT
OVER THAT AREA AND AM GETTING SOME FAIRLY HIGH SNOW TOTALS UP
THERE. DAY SHIFT MAY NEED TO UPGRADE TO A BLIZZARD WARNING IF
VISIBILITIES DO STAY DOWN.
GRADIENTS BEGIN TO EASE AFTER 21Z THIS AFTERNOON AS THE LOW TRACKS
INTO SOUTH DAKOTA. TIMING WISE...WILL KEEP ALL HEADLINES GOING AS
THEY ARE.
LONG TERM
(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 300 AM MDT SUN OCT 20 2019
WEDNESDAY...TURNING COLDER AS THE NEXT SHORTWAVE TROUGH ALOFT AND
ITS ASSOCIATED COLD FRONT MOVE ACROSS OUR COUNTIES ON NORTHWEST FLOW
ALOFT. SCATTERED TO NUMEROUS RAIN AND SNOW SHOWERS WILL SPREAD NORTH
TO SOUTH ACROSS OUR COUNTIES.
THURSDAY...DRYING OUT AND COLDER IN THE WAKE OF THE SHORTWAVE TROUGH
ALOFT AND COLD FRONT PASSAGE. COLD MAXIMUM TEMPERATURES WITH 700 MB
TEMPERATURES ONLY NEAR -11 CELSIUS.
FRIDAY...WILL SEE A SIGNIFICANT WARMING TREND AS THE FLOW ALOFT
BACKS TO NORTHWEST AND HEIGHTS AND THICKNESSES INCREASE
SUBSTANTIALLY. SURFACE LEE TROUGHING DEVELOPS WITH DOWNSLOPE WARMING
WEST WINDS HELPING TEMPERATURES TO RISE INTO THE 50S EAST OF
INTERSTATE 25.
SATURDAY...THE WEST NORTHWEST FLOW ALOFT STRENGTHENS SIGNIFICANTLY
AS ANOTHER SHORTWAVE TROUGH ALOFT AND COLD FRONT APPROACH FROM OUR
NORTH. IF THE COLD FRONTAL TIMING IS CORRECT, WE SHOULD SEE ONE MORE
MILD DAY IN THE WARM SECTOR. PERHAPS A CHANCE FOR SHOWERS ALONG AND
BEHIND THE APPROACHING COLD FRONT FOR OUR NORTHERN COUNTIES IN THE
AFTERNOON.
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 531 AM MDT SUN OCT 20 2019
WYOMING TAFS...VFR, EXCEPT OCCASIONAL MVFR AT RAWLINS AND LARAMIE
UNTIL 16Z. WIND GUSTS TO 50 KNOTS UNTIL 01Z, THEN GUSTS UP TO 30
KNOTS.
NEBRASKA TAFS...VFR. WIND GUSTS TO 50 KNOTS UNTIL 02Z, THEN GUSTS
UP TO 38 KNOTS.
FIRE WEATHER
ISSUED AT 300 AM MDT SUN OCT 20 2019
WIDESPREAD STRONG WIND EVENT WITH MOUNTAIN SNOW STILL EXPECTED
TODAY AS A LOW PRESSURE SYSTEM TRACKS ACROSS CENTRAL WYOMING INTO
SOUTHERN SOUTH DAKOTA THIS AFTERNOON. SNOW ALREADY OCCURRING OVER
AREAS WEST OF THE LARAMIE RANGE AND WINDS ARE ON THE INCREASE.
LOOKS LIKE WE COULD SEE SNOW ACROSS THE NORTHERN NEBRASKA
PANHANDLE INTO CONVERSE AND NIOBRARA COUNTIES FROM AROUND NOON
THROUGH 6 PM TODAY AS WELL. WINDS WILL BEGIN EASING BY LATE
AFTERNOON. DRIER PATTERN TUESDAY AND WEDNESDAY BEFORE NEXT LOW
PRESSURE SYSTEM APPROACHES FROM THE NORTHWEST.
CYS WATCHES/WARNINGS/ADVISORIES
WY...HIGH WIND WARNING UNTIL 6 PM MDT THIS EVENING FOR WYZ101-102-
104>109-115>119.
WINTER WEATHER ADVISORY UNTIL 6 PM MDT THIS EVENING FOR WYZ101-
102.
WINTER STORM WARNING UNTIL NOON MDT MONDAY FOR WYZ103-112-114.
BLIZZARD WARNING UNTIL 6 PM MDT THIS EVENING FOR WYZ110-113.
NE...HIGH WIND WARNING UNTIL 6 PM MDT THIS EVENING FOR NEZ002-003-
019>021-054-055-095-096.
SHORT TERM...GCC
LONG TERM...RUBIN
AVIATION...RUBIN
FIRE WEATHER...GCC
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