Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 110226
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
826 PM MDT WED SEP 10 2014

.UPDATE...
ISSUED AT 826 PM MDT WED SEP 10 2014

A FEW SHOWERS AND THUNDERSTORMS HAVE FORMED OVER WYOMING THIS
EVENING ASSOCIATED WITH A JET MAX MOVING OVER THE STATE. A SLIGHT
CHANCE SOME OF THESE COULD CLIP NORTHEAST COLORADO...SO ADDED SOME
LOW POPS TO THE FORECAST FOR THIS.

THERE ARE LOW CLOUDS JUST TO THE EAST OF THE AREA OVER NEBRASKA.
THESE CLOUDS WILL SPREAD WEST OVERNIGHT...AND POSSIBLY PRODUCE FOG
IN PLACES...THUS ADDED PATCHY FOG TO THE FORECAST FOR NORTHEAST
COLORADO.

A COLD AIRMASS IS STILL ON TRACK TO SLAM INTO NORTHEAST COLORADO
THURSDAY AFTERNOON AND THURSDAY NIGHT. THE COLDEST AIR DOES NOT
COINCIDE WITH THE BEST CHANCE FOR PRECIPITATION. THIS CONTINUES
TO MAKE IT DIFFICULT TO DETERMINE WHEN AND IF THE RAIN CHANGES
OVER TO SNOW AND HOW MUCH SNOW WILL FALL. DEPENDING ON WHEN SNOW
STARTS TO OCCUR...A FEW INCHES WILL BE POSSIBLE OVER THE EASTERN
PLAINS.

&&

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 307 PM MDT WED SEP 10 2014

MOSTLY CLEAR CONDITIONS ARE EXPECTED THROUGH THE LATE AFTERNOON
AND EVENING HOURS AS FAIR WEATHER CUMULUS DISSIPATES WITH THE LOSS
OF DAYTIME HEATING. OVERNIGHT...LOW LEVEL MOISTURE IS GOING TO BE
HELD OVER THE NORTHEAST PLAINS AS LOW LEVEL WINDS REMAIN OUT OF
THE EAST AND SOUTHEAST. BY MIDNIGHT...AREAS OF FOG AND STRATUS
SHOULD BEGIN DEVELOPING DUE TO THE BROAD UPSLOPE FLOW PATTERN. LOW
CLOUDS AND FOG SHOULD HAVE NO PROBLEM MAKING IT BACK TO THE
FOOTHILLS...AFFECTING DENVER AREA AIRPORTS. ON THURSDAY...THE
CANADIAN COLD FRONT IS EXPECTED TO BE MOVING SLOWLY ACROSS THE
NORTHERN PLAINS. SOME LIGHT RAIN OR DRIZZLE MAY DEVELOP ALONG THE
FRONT THROUGH THE DAY. LATE IN THE AFTERNOON THE FRONT IS EXPECTED
TO SURGE SOUTHWARD WITH THE LIGHT PRECIPITATION SPREADING
SOUTHWARD TO THE PALMER DIVIDE BY 6 PM. HIGH TEMPERATURES ACROSS
THE PLAINS WILL HAVE QUITE A NORTH TO SOUTH GRADIENT AS THE COOL
AIR MOVING INTO WELD AND LOGAN COUNTIES KEEPS THEM COOL WHILE THE
PALMER DIVIDE IS ABLE TO WARM BACK TO TEMPERATURES EXPERIENCED
THIS AFTERNOON.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 307 PM MDT WED SEP 10 2014

MEASURABLE RAIN MIXED WITH LIGHT SNOW OVER PORTIONS OF NE COLORADO
IS LOOKING MORE LIKELY FOR THURSDAY NIGHT INTO FRIDAY MORNING. AS
THE FRONT MOVES INTO THE REGION EARLIER IN THE AFTERNOON ON
THURSDAY WINDS WILL BEGIN TO TURN MORE NORTHEAST THURSDAY EVENING
BRINGING THE SURGE OF COLD AIR BEHIND THE FRONT DOWN INTO EASTERN
COLORADO AND WESTWARD. WINDS WITH THE FRONT WILL BE SUSTAINED FROM
15 TO 20 WITH POSSIBLE GUSTS TO 30 MPH OVER THE EASTERN PLAINS
THAT WILL DISSIPATE EARLY FRIDAY. PRECIP WILL START OUT AS MORE
STRATIFORM WITH POSSIBLE ISOLATED THUNDERSTORMS NEAR THE PALMER
DIVIDE WITH UPSLOPE AND INCREASED TEMPS IN THE AREA. AS THE FRONT
BUILDS IN MODEL SOUNDINGS ARE SHOWING A SATURATED AIRMASS TO 650
MB WITH LOW WET BULB ZERO TEMPERATURES THAT WILL BRING A MIX OF
RAIN AND SNOW LATE THURSDAY INTO THE EARLY HOURS ON FRIDAY. THE
SURFACE HIGH WILL CONTINUE TO DIP INTO THE EASTERN PORTIONS OF THE
STATE THROUGH THE LATE HOURS ON THURSDAY INTO FRIDAY. WITH DECENT
QG ASCENT AND CONTINUED UPSLOPE ALONG THE FOOTHILLS AND PALMER
DIVIDE THESE AREAS COULD SEE UP TO HALF AN INCH OF ACCUMULATION AS
THE RAIN/SNOW MIX CHANGES OVER TO SNOW BY 06Z ON FRIDAY. SREF
PLUMES HAVE STEADILY INCREASED AMOUNTS IN THESE AREAS. THE JET
PLACEMENT WILL BE JUST TO THE NORTH OF THE STATE AND WILL BRING
ENOUGH INFLUENCE TO THE NORTHERN PORTIONS OF THE CWA THAT THE
NORTHEAST CORNER COULD SEE UP TO AN INCH OF ACCUMULATION. AS FOR
THE DENVER METRO AREA THERE IS A DECENT POSSIBILITY THAT THE
COLUMN COULD GET SATURATED ENOUGH WHERE A RAIN AND SNOW MIX WILL
BE POSSIBLE EARLY FRIDAY. ANOTHER POSSIBILITY IS WITH DRYING
DIRECTLY ABOVE THIS LAYER AND A SHALLOWER AIRMASS WE COULD ONLY
SEE DRIZZLE AND FREEZING DRIZZLE. IF SNOW DOES FALL IN THE METRO
AREA ACCUMULATIONS WILL BE VERY LIGHT AND MOST LIKELY MELT
QUICKLY.

THE SURFACE HIGH OVER NEBRASKA AT 18Z WILL CONTINUE TO MOVE SOUTH
AIDING IN CONTINUED UPSLOPE CONDITIONS THAT WILL KEEP CLOUDY
CONDITIONS OVER NE COLORADO AND COOLER TEMPERATURES FOR THE
REMAINDER OF THE DAY FRIDAY. KEPT TEMPS IN THE LOW 50S BUT UPPER
40S COULD BE POSSIBLE IN SOME AREAS OVER THE PLAINS. DRIER AND
WARMER AIR WILL MOVE INTO THE MOUNTAINS WITH PREVAILING NORTHWEST
FLOW SO KEPT TEMPS IN THE UPPER 50S TO LOWER 60S. CONDITIONS WILL
BE PARTLY CLOUDY COMPARED TO DOWN ON THE PLAINS. A SURFACE TROUGH
OVER NORTHWEST CO WILL MOVE THROUGH THE REGION HELPING TO BRING
DOWNSLOPE CONDITIONS TO NE COLORADO AND CLEAR OUT THE CLOUD DECK
BY 06Z SATURDAY LEAVING ENOUGH TIME FOR POSSIBLE FOG TO DEVELOP
OVER THE PLAINS AROUND 12Z SATURDAY.

FOR SATURDAY THROUGH WEDNESDAY SURFACE HIGH PRESSURE COMBINED WITH
UPPER LEVEL RIDGING WILL BRING WARMER TEMPERATURES REACHING BACK
UP TO NEAR SEASONAL NORMALS AND DRIER CONDITIONS ACROSS NE
COLORADO. THERE IS A SLIGHT CHANCE FOR SOME ISOLATED RAIN
SHOWER/THUNDERSTORM ACTIVITY DURING THE AFTERNOONS.

&&

.AVIATION...(FOR THE TAFS THROUGH 06Z THURSDAY EVENING)
ISSUED AT 826 PM MDT WED SEP 10 2014

LOW CLOUDS WITH CEILINGS OF A 1000 FEET OR LESS ARE EXPECTED TO
MOVE IN TO THE DENVER AREA AROUND 12Z. FOG WITH VISIBILITY LESS
THAN A MILE WILL ALSO BE POSSIBLE. THE CLOUDS WILL BE SLOW TO LIFT
THURSDAY AND SKIES WILL LIKELY REMAIN BROKEN THROUGH THE DAY THURSDAY.
A COLD FRONT WILL PUSH THROUGH THURSDAY AFTERNOON...BRING GUSTY
NORTHEAST WINDS...LOWERING CEILINGS AND A CHANCE FOR RAIN. AIRMASS
MAY GET COLD ENOUGH FOR SNOW THURSDAY NIGHT...ANYTIME AFTER 03Z.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...MEIER
SHORT TERM...DANKERS
LONG TERM...BOWEN
AVIATION...MEIER



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