Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 251519
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
919 AM MDT MON APR 25 2016

.UPDATE...
ISSUED AT 855 AM MDT MON APR 25 2016

THE UPPER LOW IN NEVADA WILL SLOWLY MOVE NORTHEAST TODAY INTO
CENTRAL UTAH. SHOWERS AND SOME THUNDERSTORMS ARE EXPECTED TO
DEVELOP ACROSS THE MOUNTAINS OF COLORADO THIS AFTERNOON. PREVIOUS
FORECAST IN GOOD SHAPE...JUST EDGED UP POPS IN HIGH COUNTRY FOR
LATER THIS AFTERNOON. THERE IS SOME HINT ON NAM OF A DRY SLOT
ENDING SHOWERS FOR MANY AREAS LATE TONIGHT...WILL ADDRESS THAT IN
AFTERNOON FORECAST.

&&

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 340 AM MDT MON APR 25 2016

CURRENT SATELLITE PICTURES ARE SHOWING SOME LEE WAVE CLOUDINESS
OVER THE FOOTHILLS AND IMMEDIATE PLAINS OF THE FRONT RANGE.
SOUTHEASTERLY LOW LEVEL WINDS ARE PREDOMINATE OVER THE PLAINS
INTO THE LOWER FOOTHILLS. MODELS HAVE 50 TO 80 KNOT SOUTHWESTERLY
JET LEVEL FLOW OVER THE CWA TODAY THROUGH THIS EVENING. THEN THE
FLOW BECOMES DUE SOUTHERLY THROUGH 12Z TUESDAY MORNING WITH A
CLOSED UPPER LEVEL CIRCULATION CENTERED OVER NORTHWEST TO NORTH
CENTRAL COLORADO. THERE IS PRETTY DECENT UPWARD QG VERTICAL
VELOCITY PROGGED FOR THE CWA FROM LATE THIS MORNING WELL INTO
TUESDAY. THE BOUNDARY LAYER FLOW IS PROGGED TO BE SOUTH TO
SOUTHEASTERLY TODAY AND TONIGHT. FOR MOISTURE...THERE IS NOT VERY
MUCH PROGGED TODAY...JUST SOME MID AND UPPER LEVEL CLOUDINESS
MAINLY OVER THE WESTERN HALF OF THE CWA. MOISTURE INCREASES A BIT
TONIGHT BEST FOR THE MOUNTAINS. THERE IS SOME CAPE AROUND THIS
AFTERNOON AND OVERNIGHT. THE HIGHEST VALUES ARE IN THE MOUNTAINS
AND FOOTHILLS AROUND 00Z THIS AFTERNOON. THERE AREA A FEW AREAS
NEARING 1000 J/KG OVER THE EASTERN PLAINS FROM MID EVENING INTO
THE OVERNIGHT PERIOD. LAPSE RATES ARE PRETTY STEEP OVER THE
FOOTHILLS AND ADJACENT PLAINS BETWEEN 21Z AND 03Z LATE TODAY INTO
EARLY EVENING.  THERE IS A TAD OF MEASURABLE PRECIPITATION ON THE
QPF FIELDS THIS AFTERNOON AND THIS EVENING. THERE IS A TINY BIT
OVER THE PLAINS UNTIL 00Z THIS AFTERNOON...THEN THERE IS A BIT
MORE...MOSTLY OVER THE NORTHERN HALF. SO FOR POPS...WILL GO WITH
10-30%S OVER THE MOUNTAINS THIS AFTERNOON...WITH SOME 10-20%S FOR
THE PLAINS LATE THIS AFTERNOON. THERE MAY SOME THUNDER BUT MOSTLY
THE STORMS WILL BE WIND PRODUCERS OUT ON THE PLAINS.  WILL
INCREASE THE POPS THIS EVENING IN THE MOUNTAINS TO 30-50%S WITH
SNOW WELL DOWN INTO THE FOOTHILLS BY 12Z. FOR THE PLAINS...POPS
WILL BE IN THE 10% SOUTH TO 50% NORTH RANGE OVERNIGHT. THERE MAY
BE A TAD OF SNOW MIXED IN FOR 1-2 HOURS BEFORE 12Z MOSTLY ABOVE
5000 FEET. NO ACCUMULATIONS. NO HIGHLIGHTS. FOR TEMPERATURES
...TODAY`S HIGHS LOOK TO BE 1.0-3.5 C WARMER THAN SUNDAY`S HIGHS.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 111 AM MDT MON APR 25 2016

UPPER LEVEL CLOSED LOW WILL MOVE INTO THE REGION BY TUESDAY
MORNING BRINING CONTINUED RAIN/SNOW TO THE MOUNTAINS AND RAIN ON
THE PLAINS BY FRIDAY AFTERNOON/EVENING. A STRONG SURFACE LOW WILL
BE OVER THE EASTERN PLAINS TUESDAY WITH HELP TO KEEP PRECIPITATION
OUT OF SE CO BUT WILL BRING SOME INCREASED MOISTURE TO NE CO AND
THE MOUNTAINS. COOLER AIR BEHIND THE EXITING SFC LOW WILL BRING
INCREASED CHANCES OF A RAIN AND SNOW MIXTURE DOWN INTO THE LOWER
FOOTHILLS AND URBAN CORRIDOR BY TUESDAY EVENING. MODELS STILL
SUGGESTING THAT A MAJORITY OF THE ACCUMULATING SNOWFALL WILL BE
OVER THE HIGHER ELEVATIONS WITH UPWARDS OF 6 INCHES POSSIBLE BY
INTENSITY MORNING.

FOR WEDNESDAY A COOLER TREND TAKES HOLD WITH HIGHS ROUGHLY 10
DEGREES BELOW NORMAL WITH TEMPS IN THE 50S AND LOWS HOVERING
AROUND FREEZING FOR THE LATTER HALF OF THE WEEK INTO THE WEEKEND.
ON WEDNESDAY SUBSIDENCE WILL START TO BUILD IN WITH AN UPPER LEVEL
RIDGE DRYING OUT CONDITIONS ON THE PLAINS BUT KEEPING A SLIGHT
CHANCE OF RAIN IN THE MOUNTAINS DUE TO SOME LOW LEVEL MOISTURE.

IN THE EXTENDED MODELS THE NEXT STORM SYSTEM IS STARTING TO TAKE
SHAPE. 00Z EC HAS THE LOW CENTER FURTHER SOUTH THEN THE 00Z GFS
WITH THE CANADIANS MORE IN LINE WITH THE EC. THE GFS CURRENTLY
HAS A MORE FAVORABLE UPSLOPE OUTCOME WITH INCREASING MOISTURE
THROUGH SATURDAY. MODEL SOUNDINGS SHOW TEMPERATURES HIGH ENOUGH ON
THE PLAINS TO BRING RAIN OR GRAUPEL VS SNOW BUT WITH EVAPORATIVE
COOLING AND CONTINUED PRECIPITATION CANNOT RULE OUT SNOW ON THE
PLAINS COME SATURDAY EVENING. THIS SYSTEM WILL CONTINUE THROUGH
SATURDAY WITH ANOTHER FOLLOWING CLOSELY BEHIND ON SUNDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING) ISSUED
AT 917 AM MDT MON APR 25 2016

SOUTHEAST WINDS WILL PERSIST TODAY...THEN GO TO A DRAINAGE SOUTH WIND
OVERNIGHT. TOMORROW A FRONT WILL DROP ACROSS THE AREA IN THE
AFTERNOON...WITH WINDS BECOMING NORTHERLY. THE AIRMASS WILL BECOME
INCREASINGLY MOIST AND UNSTABLE...AND ISOLATED THUNDERSTORMS ARE
POSSIBLE FROM MID AFTERNOON THROUGH THE EVENING...WITH ISOLATED
SHOWERS POSSIBLE OVERNIGHT. SOME GUSTS TO 35 KNOTS WILL BE
POSSIBLE NEAR THE THUNDERSTORMS THIS AFTERNOON AND EVENING.

&&

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

$$

UPDATE...RTG
SHORT TERM...RJK
LONG TERM...BOWEN
AVIATION...RJK



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