Area Forecast Discussion
Issued by NWS Cheyenne, WY

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FXUS65 KCYS 140532
AFDCYS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHEYENNE WY
1132 PM MDT SUN JUL 13 2014

.UPDATE...
ISSUED AT 847 PM MDT SUN JUL 13 2014

SHOWER AND TSTM CHANCES APPEAR TO HAVE ENDED FOR TONIGHT. LATEST
WATER VAPOR SATELLITE AND OBJECTIVE UPPER AIR ANALYSIS SHOW THE
BEST LARGE SCALE ASCENT SHIFTING OFF TO THE EAST WITH A VIGOROUS
MIDLVL SHORTWAVE MOVING ACROSS THE CENTRAL PLAINS. AIR MASS SHOULD
CONTINUE TO STABILIZE WITH THE LOSS OF DIURNAL HEATING. INCREASING
SUBSIDENCE ALOFT AND NEGATIVE THETA-E ADVECTION ALOFT DURING THE
OVERNIGHT SHOULD ELIMINATE ANY RISK FOR MEASURABLE PCPN. BUMPED UP
MINIMUM TEMPS A BIT AS LLVL AIR MASS STILL PRETTY MOIST AND HIRES
MODELS KEEP DEWPOINTS IN THE 50S TO NEAR 60F THROUGH MOST OF THE
NIGHT. THERE IS A SLIGHT POSSIBILITY OF SOME FOG TONIGHT IN A FEW
LOCATIONS...ESPECIALLY CHEYENNE GIVEN SIGNIFICANT RAIN AND HAIL
EARLIER TODAY. CONFIDENCE IN THIS SCENARIO IS QUITE LOW GIVEN
THE WESTERLY COMPONENT TO WINDS ON BOTH FCST OUTPUT AND OBS. FOR
THAT REASON HAVE OPTED NOT TO MENTION THAT IN THE GRIDS ATTM.

&&

.SHORT TERM...(THIS EVENING THROUGH TUESDAY NIGHT)
ISSUED AT 337 PM MDT SUN JUL 13 2014

CONVECTION GRADUALLY INCREASING ACROSS SOUTHEAST WYOMING THIS
AFTERNOON AND THIS WILL MOVE EAST OVER THE NEBRASKA PANHANDLE THIS
EVENING. HEAVY RAIN CONTINUES TO BE THE MAIN THREAT FROM STRONGER
STORMS WITH MOST LIKELY AREA FOR THIS BEING EAST OF THE MTNS INTO
THIS EVENING. ANY FLOODING THAT MIGHT OCCUR SHOULD REMAIN RATHER
LOCALIZED. SOME HAIL THREAT STILL THERE AS WELL THOUGH UPPER
SUPPORT NOT ALL THAT GREAT. ACTIVITY WILL DECREASE OVERNIGHT
THOUGH SOME MAY HANG ON OVER NORTHEAST PARTS OF THE CWA THROUGH
THE NIGHT.

SIMILAR SCENARIO EXPECTED FOR SATURDAY AS SFC UPSLOPE FLOW BEHIND
A WEAK SFC FRONT THAT WILL PASS ACROSS DURING THE DAY ALLOWS FOR
REDEVELOPMENT OF CONVECTION. INSTABILITY NOT PROGGED TO BE AS
GREAT THOUGH SO ACTIVITY LIKELY TO BE MORE SHOWERY IN NATURE.
TEMPS JUST A LITTLE COOLER OVER THE PLAINS. ACTIVITY WILL DIE OUT
SAT EVENING. A STRONGER FRONT WILL THEN PUSH SOUTH ACROSS THE CWA
SUNDAY WITH SCTD SHOWERS AND A FEW STORMS ONCE AGAIN.

.LONG TERM...(WEDNESDAY THROUGH SUNDAY)
ISSUED AT 337 PM MDT SUN JUL 13 2014

A WEAK SHORTWAVE IS EXPECTED TO EXIT THE AREA WEDNESDAY EVENING
WHICH WILL CAUSE SHOWERS AND THUNDERSTORMS TO GRADUALLY EXIT THE
AREA EAST OF THE LARAMIE RANGE BY AROUND MIDNIGHT. MEANWHILE...THE
UPPER LEVEL RIDGE WILL CONTINUE TO BUILD OVER THE ROCKIES BEGINNING
THURSDAY AND CONTINUING THROUGH THE WEEKEND. SMALL DISTURBANCES ARE
PROGGED TO MOVE THROUGH THE EASTERN PERIPHERY OF THIS RIDGE THURSDAY
AND FRIDAY WHICH MAY TRIGGER SOME CONVECTION EAST OF THE LARAMIE
RANGE. THE NEXT STRONG UPPER LEVEL TROF IS PROGGED TO MOVE INTO
BRITISH COLUMBIA AND SASKATCHEWAN THIS WEEKEND WHICH WILL TEND TO
AMPLIFY THE RIDGE OVER THE REGION WHICH WILL RESULT IN WARMING
TEMPERATURES AND SOMEWHAT DRIER CONDITIONS.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY EVENING)
ISSUED AT 1132 PM MDT SUN JUL 13 2014

LIGHT WINDS AND SCT MID/HIGH CLOUDS WILL PREVAIL OVERNIGHT ACROSS
THE FORECAST AREA. A FEW THUNDERSTORMS ARE EXPECTED TO DEVELOP ALONG
AND WEST OF THE LARAMIE RANGE MONDAY AFTERNOON WITH GUSTY WINDS AND
LIGHT RAIN ANTICIPATED FROM THIS ACTIVITY.  NORTHEAST WINDS WILL
INCREASE BETWEEN 16 AND 19Z ACROSS THE EASTERN PLAINS...WITH GUSTS
TO 20 KTS LOOKING TO OCCUR THROUGH THE AFTERNOON. WINDS WILL EASE
AND THUNDERSTORMS WILL DIMINISH THROUGH THE EVENING.

&&

.FIRE WEATHER...
ISSUED AT 337 PM MDT SUN JUL 13 2014
CONCERNS TO REMAIN LOW INTO NEXT WEEK WITH WEATHER CONDITIONS
REMAINING NON-CRITICAL. SCATTERED THUNDERSTORMS WILL OCCUR MOST
AFTERNOONS AND EVENINGS THROUGH SUNDAY THEN BECOME MORE ISOLATED
NEXT WEEK. DRY LIGHTNING NOT EXPECTED WITH MONSOONAL MOISTURE OVER
THE REGION.

&&

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...NONE.
NE...NONE.
&&

$$

UPDATE...HAMMER
SHORT TERM...REC
LONG TERM...REC
AVIATION...RJM
FIRE WEATHER...RUBIN






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