Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 191555
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
955 AM MDT SUN APR 19 2015

.UPDATE...
ISSUED AT 955 AM MDT SUN APR 19 2015

THE SHOWERS OVER THE PLAINS HAVE MOVED SOUTHEAST OF THE AREA. A
DRIER NORTHERLY FLOW WILL PREVAIL OVER THE EASTERN PLAINS TODAY
AND REMOVED THE MENTION OF SHOWERS FROM THE FORECAST. IT WILL BE
WINDY OVER EASTERN COLORADO TODAY WITH NORTHERLY GUSTS TO 40 MPH.
OVER THE MOUNTAINS...CROSS SECTIONS SHOWS MOISTURE REMAINING IN
PLACE THROUGH THE DAY. WILL KEEP MOSTLY CLOUDY SKIES IN THE
FORECAST WITH SCATTERED SHOWERS. ANY SNOW ACCUMULATION SHOULD BE
LIGHT AND LESS THAN 2 INCHES.

ANOTHER WAVE IN THE NORTHWEST FLOW ALOFT WILL RACE SOUTHEAST
ACROSS THE STATE LATE TONIGHT AND EARLY MONDAY. THIS MAY BRING A
ROUND OF SHOWERS TO THE AREA. THE 12Z NAM...GFS AND GEM HAVE ALL
TRENDED WETTER WITH THE LATEST RUNS. THEY SHOW AN INCREASE IN THE
COVERAGE OF SHOWERS TONIGHT...ESPECIALLY ALONG THE FRONT RANGE.

CURRENTLY THIS WAVE IS OVER SOUTHERN ALBERTA. WILL WATCH HOW THIS
SYSTEM PROGRESSES THROUGH THE DAY. WILL INCREASE POPS FOR THIS
INTO THE 40-70 PERCENT RANGE. MAY NEED TO INCREASE POPS MORE IF
CONFIDENCE INCREASES. APPEARS THIS SYSTEM WILL BE COLD ENOUGH FOR
MAINLY SNOW. CURRENT MODELS SHOW A QUARTER INCH OR LESS OF
PRECIPITATION. COULD SEE SLUSHY ROADS FOR THE MORNING COMMUTE IN
SOME LOCATIONS.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 424 AM MDT SUN APR 19 2015

BAND OF SHOWERS ON THE BACK EDGE OF THE UPPER LOW DROPPING THROUGH
DENVER NOW...AND SHOULD BE CLEAR OF OUR FORECAST AREA BY MID
MORNING. COOL AND DRIER AIRMASS UPSTREAM...BUT STILL SOME CLOUDS
AND SHALLOW CONVECTION SO I WILL HANG ON TO THE LOW POPS FOR TODAY
AND DROP THE HIGHS SLIGHTLY. IN THE LATE AFTERNOON AND EVENING
WARM ADVECTION ALOFT KICKS IN AND THIS SHOULD CAP THE CONVECTION
DURING THIS PERIOD...BUT THIS QUICKLY LEADS TO ANOTHER MOIST LAYER
WITH NEUTRAL STABILITY THAT SHOULD BRING SOME LIGHT SNOW TO THE
MOUNTAINS...MORE CLOUDS FOR THE PLAINS AGAIN...AND POSSIBLY A FEW
SHOWERS MAKING IT OFF THE MOUNTAINS LATER TONIGHT. THIS DOES NOT
LOOK LIKE MUCH...BUT AGAIN ENOUGH FOR THE LOW POPS. HOW SOON IT
CLOUDS UP WILL DETERMINE LOW TEMPERATURES TONIGHT. AIRMASS IS
LOOKING A LITTLE COLDER THAN WHAT WE HAD SEEN EARLIER...BUT THE
CLOUDS COULD OFFSET IT. FOR NOW IT DOES LOOK LIKE THERE WILL BE
WIDESPREAD FREEZING TEMPERATURES WITH LOWS IN THE UPPER 20S IN
MOST AREAS TONIGHT.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 424 AM MDT SUN APR 19 2015

WEST-NORTHWESTERLY FLOW ALOFT IS PROGGED FOR THE FORECAST AREA
MONDAY THROUGH TUESDAY...WITH AN UPPER RIDGE AXIS MOVING INTO
COLORADO TUESDAY NIGHT. THE SPEEDS AT JET LEVEL ARE PRETTY WEAK
AND BY TUESDAY NIGHT THE FLOW IS VERY WEAK AND DUE WESTERLY.
THE SYNOPTIC SCALE ENERGY IS BENIGN THROUGH THE PERIODS ACCORDING
TO THE QG VERTICAL VELOCITY FIELDS. THE BOUNDARY LAYER FLOW IS
DOMINATED BY A WEAK PRESSURE GRADIENT THROUGH THE FOUR PERIODS AND
WIND SPEEDS ARE NOT VERY STRONG WITH WEAK NORMAL DIURNAL PATTERNS
EXPECTED. FOR MOISTURE...THERE IS QUITE A BIT OVER THE CWA ON
MONDAY WELL INTO THE EVENING...BEFORE DRYING OVERNIGHT. TUESDAY
IS FAIRLY DRY...WITH SOME IN THE MID LEVELS FOR LATE IN THE DAY.
TUESDAY NIGHT IS PRETTY DRY. THERE IS SOME MEAGER CAPE OVER THE
MOUNTAINS AND FOOTHILLS LATE DAY MONDAY. THERE IS A BIT MORE LATE
DAY TUESDAY...AND EVEN SOME OVER THE WESTERN PLAINS. THE HIGHEST
VALUES ARE UNDER 1000 J/KM AND OVER THE FOOTHILLS. MODELS SHOW A
MINOR THETA-E AXIS OVER CENTRAL COLORADO TUESDAY AFTERNOON. THERE
ARE PRETTY STEEP LAPSE RATES OVER THE CWA MONDAY AFTERNOON. BUT
THERE IS A MID LEVEL STABLE LAYER OVER THE EASTERN PLAINS. THE
LAPSE RATES ARE A BIT STEEPER FOR TUESDAY AFTERNOON. THE QPF
FIELDS HAVE SMALL AMOUNTS OF MEASURABLE PRECIPITATION FOR THE
MOUNTAINS MONDAY MORNING...THE SMALL AMOUNTS FOR THE MOUNTAINS AND
ADJACENT PLAINS MONDAY AFTERNOON AND EVENING. THERE IS NOTHING
PROGGED OVERNIGHT TUESDAY AND TUESDAY MORNING. THERE IS A BIT OF
PRECIPITATION AGAIN OVER THE MOUNTAINS...FOOTHILLS AND ADJACENT
PLAINS FOR THE TUESDAY AFTERNOON AND EVENING...THEN NOTHING
TUESDAY NIGHT. FOR POPS...10-40%S MONDAY AND MONDAY EVENING FOR
THE WESTERN HALF OF THE CWA...THEN 10-30%S FOR THE MOUNTAINS FROM
THE DIVIDE EAST INTO THE WESTERN HALF OF THE PLAINS LATE DAY
TUESDAY. FOR TEMPERATURES...MONDAY`S HIGHS ARE 0.5-2.0 C WARMER
THAN TODAY`S HIGHS. TUESDAY`S HIGHS ARE 3-4 C WARMER THAN
MONDAY`S. FOR THE LATER DAYS...WEDNESDAY THROUGH SATURDAY...MODELS
NOW SHOW AND UPPER RIDGE OVER COLORADO WEDNESDAY AND THURSDAY WITH
A WEAK UPPER TROUGH MOVING IN LATE THURSDAY NIGHT INTO FRIDAY
AFTERNOON. UPPER RIDGING RETURNS FOR FRIDAY NIGHT AND SATURDAY.
MOISTURE IS JUST FAIR WITH THE TROUGH.

&&

.AVIATION...(FOR THE TAFS THROUGH 18Z MONDAY MORNING)
ISSUED AT 955 AM MDT SUN APR 19 2015

CEILINGS OF 2500 TO 3500 FEET FROM DENVER SOUTH WILL SLOWLY RISE
THROUGH 18Z. FROM 18Z THROUGH THE EVENING...SCATTERED TO BROKEN
SKY COVERAGE IS EXPECTED WITH CLOUDS HEIGHTS MAINLY 5000 TO 10000
FEET. NORTHERLY WINDS ARE EXPECTED TO PREVAIL TODAY AND TONIGHT.
GUSTS TO 30 KNOTS WILL BE POSSIBLE THROUGH 00Z.

A SYSTEM WILL DIVE SOUTHEAST ACROSS NORTHEAST COLORADO LATE
TONIGHT...AFTER 06Z. SCATTERED SHOWERS WILL DEVELOP AND CEILINGS
WILL FALL LATE TONIGHT AND EARLY MONDAY MORNING. AIRMASS WILL BE
COLD ENOUGH WITH THIS SYSTEM FOR SNOW. IT WILL BE A WEAK QUICK
MOVING SYSTEM...SO ANY SNOW ACCUMULATION WILL BE LIGHT.

&&

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

$$

UPDATE...MEIER
SHORT TERM...GIMMESTAD
LONG TERM...RJK
AVIATION...MEIER



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