Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 230346
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
946 PM MDT TUE JUL 22 2014

.UPDATE...
ISSUED AT 946 PM MDT TUE JUL 22 2014

A FEW MINOR CHANGES COMING. STORMS IN PARK COUNTY HAVE BEEN
SLOSHING AROUND THE VALLEY...THEY HAVE ALMOST USED UP THE
AVAILABLE ENERGY AND WILL EITHER BE DISSIPATING OR MOVING
SOUTHEAST OUT OF THE COUNTY SOON.

EAST WINDS INTO NE COLORADO ARE A BIT STRONGER THAN EXPECTED AND
ARE BRINGING IN WARM MOIST AIR THAT IS WEAKLY CAPPED. WATCHING
A SERIOUS STORM AROUND CHADRON NEBRASKA DROPPING SOUTH THROUGH A
FAVORABLE AIRMASS...THOUGH THERE IS A BIT DRIER AIR AHEAD OF IT.
SOME CHANCE THIS COULD CLIP THE NE CORNER OF COLORADO AFTER
MIDNIGHT. MORE LIKELY OUTFLOW FROM THIS STORM...OR LOW LEVEL
CONVERGENCE IN THE EXISTING MOISTURE PLUME...COULD TRIGGER NEW
STORMS IN OUR AREA. CURRENT FORECAST ALREADY HAS SOME LOW POPS FOR
THIS IDEA...I WILL BUMP THEM UP SOME. GIVEN THE AMOUNT OF MOISTURE
VERSUS SHEAR I WOULD EXPECT STRONG PULSES ON BOUNDARIES TO BE THE
DOMINANT MODE...BUT THERE COULD BE SOME THREAT OF SEVERE HAIL AND
HEAVY RAIN. FOR THE DENVER AREA THE FORECAST IS LOOKING
GOOD...COULD HAVE SOME STRATUS IF WE GOT OUTFLOW FROM NEARBY
STORMS...BUT NOT LOOKING LIKELY AT THIS POINT.

&&

.SHORT TERM...(THIS EVENING THROUGH WEDNESDAY)
ISSUED AT 338 PM MDT TUE JUL 22 2014

TOWERING CUMULUS HAS BEEN CONFINED TO THE FRONT RANGE MOUNTAINS
AND FOOTHILLS...AND PARK COUNTY SO FAR...WITH ANY PRECIPITATION
JUST SOUTH OF THE FORECAST AREA TOWARD THE PIKES PEAK REGION.
STILL EXPECT ISOLATED SHOWERS/STORMS TO DEVELOP IN THE FRONT RANGE
MOUNTAINS AND FOOTHILLS LATE THIS AFTERNOON. IN THE LOWER
ELEVATIONS...THE CAP IS WEAKENING AS WE HAVE HAD FULL SUNSHINE
THROUGH THE DAY. LATEST ACARS SOUNDINGS SHOW IF WE REACH 95 NEAR
DENVER WE COULD BREAK THE CAP. AT THIS TIME...IT WOULD STILL BE
MORE LIKELY FOR THIS TO OCCUR ALONG THE ELEVATED TERRAIN OF THE
PALMER DIVIDE OR CHEYENNE RIDGE. THE LATEST HRRR AND RAP13 HINT
AT THIS...SO WILL CONTINUE THE LOW POPS IN/NEAR THOSE AREAS. ONLY
CHANGE TO WEATHER WAS TO ADD SOME LOW POPS OVER THE NORTHEAST
PLAINS LATE THIS EVENING AND OVERNIGHT AS LOW LEVEL JET AND
MOISTURE CONVERGENCE INCREASE. HOWEVER...THIS OCCURS UNDER A LARGE
DOMINATING RIDGE SO ONLY A SLIGHT CHANCE OF BREAKING THROUGH THE
CAP AT THIS POINT.

AREAS OF STRATUS MAY DEVELOP OVER THE EASTERN PLAINS AS WELL WITH
CONTINUED ADVECTION OF LOW LEVEL MOISTURE IN UPSLOPE
EAST/SOUTHEAST FLOW.

ON WEDNESDAY...LOW LEVEL FLOW TURNS FROM SOUTHEAST TO MORE
SOUTHERLY AS LEE TROUGH STRENGTHENS. LOOKS LIKE DENVER CONVERGENCE
ZONE WILL GET ERODED AS LEE TROUGH DEVELOPS AND STRONGER MIXING
OCCURS. AS A RESULT...BEST MOISTURE WILL LIKELY SHIFT NORTHWARD TO
NEAR THE WYOMING BORDER AREA BY AFTERNOON. CAPES THERE MAY REACH
1000-1500 J/KG WITH A STRONGER STORM POSSIBLE. ELSEWHERE...LOOKS
LIKE CONVECTION WILL BE HIGHER BASED WITH STRONG GUSTY OUTFLOW
WINDS AND BRIEF MODERATE RAIN. STORM COVERAGE WILL BE HIGHEST IN
MOUNTAINS WHERE A MID LEVEL MOISTURE PLUME IS EXPECTED TO ARRIVE
BY MID/LATE AFTERNOON.

.LONG TERM...(WEDNESDAY NIGHT THROUGH TUESDAY)
ISSUED AT 338 PM MDT TUE JUL 22 2014

SOME THUNDERSTORMS WILL CONTINUE WEDNESDAY EVENING...MAINLY ACROSS
THE MOUNTAINS. MAIN THREAT TO BE GUSTY OUTFLOW WINDS AS LOW LEVEL
MOISTURE WILL BE LIMITED. STORMS SHOULD END AROUND MIDNIGHT AS
AIRMASS STABILIZES. ON THURSDAY...UPPER RIDGE WILL BE OVER THE
AREA WITH THE CENTER OF HIGH OVER CENTRAL NEW MEXICO. RIDGE GETS
FLATTENED A BIT AS MID LEVEL SHORTWAVE MOVES ACROSS NORTHERN
COLORADO WITH FLOW ALOFT BECOMING A BIT MORE WESTERLY. THERE IS
SOME INCREASE IN MONSOON TYPE MOISTURE INTO COLORADO...MAINLY
ACROSS THE MOUNTAINS. THIS WILL PROVIDE FOR A CHANCE OF AFTERNOON
AND EVENING THUNDERSTORMS...WITH THE BEST CHANCE OVER THE
MOUNTAINS. STORMS TO PRODUCE GUSTY WINDS WITH BRIEF MODERATE RAIN.
FOR FRIDAY...UPPER RIDGE REMAINS OVER THE AREA WITH WESTERLY FLOW
ALOFT. MODELS INDICATE ANOTHER INFLUX OF MONSOONAL MOISTURE FLOW
INTO THE AREA...MAINLY ACROSS THE MOUNTAINS. DAYTIME HEATING TO
GENERATE SOME THUNDERSTORMS DURING THE AFTERNOON AND EVENING. A
WEAK SURFACE FRONT LOOKS TO MOVE ACROSS THE NORTHEAST PLAINS WITH
SOME SLIGHT LOW LEVEL COOLING. THIS MAY LIMIT THE THUNDERSTORM
CHANCES ACROSS THE PLAINS AND WILL KEEP THE BEST CHANCE FOR
THUNDERSTORMS OVER THE MOUNTAINS. HIGHS TO BE A FEW DEGREES COOLER
ACROSS NORTHEAST COLORADO...BUT SHOULD STILL BE IN THE LOWER AND
MIDDLE 90S. ON SATURDAY...MODELS SHOW THE UPPER RIDGE RETROGRADING
A BIT WITH THE FLOW ALOFT OVER COLORADO BECOMING WEST NORTHWEST.
MODELS SHOW SOME DECREASE IN THE MONSOON MOISTURE WITH MOST OF THE
MOISTURE BEING DISPLACED OVER SOUTHERN COLORADO. GFS STILL DRIER
THAT THE ECMWF...ESPECIALLY AT LOW LEVELS. WILL CONTINUE WITH A
SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS. THERE
APPEARS TO BE A MID LEVEL SHORTWAVE WHICH MOVES ACROSS ACROSS
NORTHEAST COLORADO DURING THE AFTERNOON...PUSHING ANOTHER WEAK
FRONT INTO THE AREA. LIFT WITH THIS WAVE MAY HELP INCREASE THE
THUNDERSTORM CHANCES. FOR NOW WILL KEEP THE BEST CHANCE OVER THE
HIGH COUNTRY. HIGHS TO BE IN THE LOW AND MID 90S ACROSS THE
PLAINS.

FOR THE LATER DAYS...SUNDAY THROUGH TUESDAY. FLOW ALOFT TO BECOME
NORTHWEST SUNDAY. BOTH ECMWF AND GFS SHOW A SURFACE HIGH MOVING
INTO NORTHEAST PLAINS WITH LOW LEVEL FLOW BECOME SOUTHEAST. THIS
WILL HELP BRING SOME LOW LEVEL MOISTURE INTO THE AREA. FOR NOW
WILL KEEP THE BEST CHANCE OF THUNDERSTORMS OVER THE MOUNTAINS.
COOLER AIRMASS WITH HIGHS IN THE MID 80S ACROSS THE PLAINS.
NORTHWEST FLOW ALOFT CONTINUES MONDAY AND TUESDAY WITH HIGHS
SLIGHTLY BELOW AVERAGE ACROSS NORTHEAST COLORADO. ENOUGH MOISTURE
FOR A SLIGHT CHANCE OF AFTERNOON AND EVENING THUNDERSTORMS EACH
DAY...MAINLY OVER THE MOUNTAINS.

&&

.AVIATION...(FOR THE TAFS THROUGH 00Z WEDNESDAY LATE AFTERNOON)
ISSUED AT 946 PM MDT TUE JUL 22 2014

VFR EXPECTED THROUGH WEDNESDAY. LOW LEVEL MOISTURE WILL INCREASE
OVERNIGHT AND THERE IS A CHANCE OF SOME STRATUS BELOW 1000 FT AGL.
ALSO EXPECTING A DENVER CYCLONE TO DEVELOP TOWARD MORNING...FOR
NOW FORECASTING LIGHT WINDS AT KDEN/KAPA AROUND SUNRISE BUT THE
WINDS COULD BE NW FOR A WHILE. ON WEDNESDAY...SOUTHERLY WINDS
WILL DEVELOP AND INCREASE TO 12G20KTS BY 18Z-21Z. ONLY A SLIGHT 20
PERCENT CHANCE OF STORMS AFTER 21Z.

&&

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

$$

UPDATE...GIMMESTAD
SHORT TERM...BARJENBRUCH
LONG TERM...D-L
AVIATION...GIMMESTAD



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