Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 261027
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
427 AM MDT SUN APR 26 2015

.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 425 AM MDT SUN APR 26 2015

UPPER LEVEL LOW CENTER OF WEST CENTRAL ARIZONA WILL MOVE ACROSS
CENTRAL ARIZONA TODAY AND CENTRAL NEW MEXICO TONIGHT. THIS IS A
LITTLE MORE SOUTH THAN THE MODELS WERE SHOWING. THIS WILL RESULT IN
SLIGHTLY LOWER PRECIPITATION AMOUNTS.

STEEP LAPSE RATES OVER THE AREA COMBINED WITH CONVERGENCE ALONG THE
BOUNDARY PRODUCED THUNDERSTORMS OVERNIGHT OVER THE PLAINS. THE
STORMS GENERALLY MOVED NORTHWARD WITH THE FLOW ALOFT AND DEVELOPMENT
SHIFTED WESTWARD WITH THE BOUNDARY. STRENGTHENING EASTERLY WINDS
WILL HELP PUSH THIS BOUNDARY WESTWARD THROUGH THE EARLY MORNING
HOURS. EXPECT SHOWERS AND THUNDERSTORMS TO CONTINUE TO FIRE ALONG
THIS CONVERGENCE LINE THROUGH THE EARLY MORNING HOURS AS IT SHIFTS
WESTWARD INTO THE METRO AREA.

BY MID TO LATE MORNING...EASTERLY WINDS WILL PREVAIL ALONG THE FRONT
RANGE. THIS MOIST EASTERLY UPSLOPE FLOW SHOULD CONTINUE TO PRODUCE
LIGHT TO MODERATE RAIN ALONG THE FRONT THROUGH TONIGHT. THE FLOW
WILL SLOWLY WEAKEN OVERNIGHT...SO WILL LOWER PRECIPITATION AMOUNTS A
LITTLE. WILL UPGRADE THE WATCH TO A WARNING. AMOUNTS WILL BE A
LITTLE LOWER THAN THE CURRENT WATCH DUE TO THE LITTLE MORE SOUTHERLY
TRACK. STILL THINKING 8 TO 16 INCHES OF SNOW ALONG THE EAST SLOPES.
FOOTHILLS SHOULD SEE MAINLY RAIN TODAY...WITH A CHANGE TO SNOW FOR
THE HIGHER FOOTHILLS THIS EVENING. PRECIPITATION DECREASE OVERNIGHT
AS THE TEMPERATURES AND SNOW LEVELS FALL IN THE FOOTHILLS...SO WILL
NOT ISSUE ANY ADVISORIES OR WARNINGS AT THIS TIME. COULD SEE UP TO 8
INCHES OF SNOW IN THE HIGHER FOOTHILLS BY MONDAY MORNING...BUT MOST
LOCATIONS SHOULD BE UNDER 4 INCHES.

OVER THE PLAINS...IT WILL REMAIN MOIST...HOWEVER THERE IS A LACK OF
LARGE SCALE FORCING. WILL KEEP POPS HIGH...BUT PRECIPITATION AMOUNTS
SHOULD BE ON THE LIGHT SIDE.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 425 AM MDT SUN APR 26 2015

BY EARLY MON MORNING...MODEL CONSENSUS PLACES THE CLOSED 500 MB
LOW ABOUT 100 MILES WEST-SOUTHWEST OF AMARILLO TX. LOW LOOKS
SOMEWHAT STRONGER AT THIS POINT AND CONSEQUENTLY SLOWER MOVING.
BEST HEIGHT FALLS ARE INDICATED DUE EAST OF THE LOW WHICH WOULD
SUPPORT ITS EASTWARD PROGRESS PORTRAYED IN THE MODELS. EAST-
NORTHEASTERLY FLOW AROUND THE NORTH SIDE OF THIS CYCLONE WILL
LIKELY CONTINUE TO PRODUCE AMPLE CLOUD COVER AND AREAS OF LIGHT
PRECIPITATION OVER THE FRONT RANGE MTNS AND ADJACENT HIGH PLAINS OF
NORTHEAST COLORADO DURING THE MORNING HRS ON MONDAY. HEIGHT OF
THE WETBULB ZERO AROUND 12Z/MONDAY IS FCST TO BE ANYWHERE FROM
7400 FT OVER NRN PORTIONS OF THE I-25 CORRIDOR TO AROUND 8000 FT
OVER THE PALMER DVD. THEREFORE NOT COLD ENOUGH FOR SNOW ON THE
PLAINS...BUT CERTAINLY COLD ENOUGH FOR A RAIN/SNOW MIX OVER THE
HIGHER TERRAIN OF THE PALMER DIVIDE. ITS POSSIBLE WE COULD SEE
AREAS OF LIGHT SNOW ACCUMULATION ABOVE 6500 FT OR SO ON THE DIVIDE
MON MORNING. MEANWHILE THE HIGHER EAST FACING SLOPES OF THE FRONT
RANGE MTNS AND FOOTHILLS COULD PICK UP ANOTHER 1 TO 3 INCHES OF
SNOW BY LATE MON MORNING...WITH THE GREATER AMTS CENTERED AROUND
8500 FT WITHIN THE FAVORABLE 25-30F TEMP ZONE. BY ERLY MON
AFTERNOON SHOULD SEE PRECIP ENDING FROM EAST-TO-WEST ON THE PLAINS
WITH AN INFLUX OF DRIER AIR WRAPPING AROUND THE UPPER LOW. THIS
DRYING TREND WILL CONTINUE THROUGH THE AFTERNOON AND EVENING HOURS
WITH THE LOW-LEVEL FLOW TURNING TO A LESS FAVORABLE NORTHERLY
COMPONENT WHICH SHOULD BRING AN END TO THE LIGHT PRECIP ON THE
PLAINS BEFORE MIDNIGHT AND OVER HIGHER ELEVATIONS OF THE FRONT
RANGE BY TUE MORNING. SHOULD SKIES CLEAR SOONER THAN EXPECTED
OVERNIGHT...COULD SEE A HARD FREEZE FOR PORTIONS OF THE HIGH
PLAINS AND CERTAINLY FOR THE PALMER DIVIDE. AS IT STANDS NOW...
ELEVATIONS BELOW 6000 FT SHOULD ESCAPE A FREEZE.

LATER IN THE WEEK...THE REGIONAL AIRMASS DRIES AND STEADILY WARMS
AS A STRONG UPPER RIDGE NOSES IN FROM THE GREAT BASIN. HOWEVER
LINGERING LOW-LEVEL MOISTURE STREAMING NORTH BENEATH THE RIDGE
COULD BUBBLE UP INTO A FEW LATE DAY SHOWERS/T-SHOWERS OVER THE
HIGHER ELEVATIONS TUE AFTERNOON. OTHERWISE TEMPS NEAR AVERAGE ON
TUESDAY JUMP ANOTHER UP ANOTHER 4-5DEG C FOR WEDNESDAY WITH
VIRTUALLY NO CHANCE OF PRECIP THAT DAY WITH THE UPPER RIDGE AXIS
PASSING OVERHEAD. ON THURSDAY...FLOW ALOFT TURNS SWLY WITH RIDGE
TO OUR EAST AND A SHORTWAVE TROUGH SWINGING DOWN OUT OF THE PAC
NORTHWEST. A RIBBON OF MOISTURE FLOWING IN OFF THE PACIFIC AHEAD
OF THIS TROUGH ACCORDING TO MODELS APPEARS TO FUEL A WEST-EAST
BAND OF SHOWERS-T-STORMS ACRS NORTHERN AND CNTRL COLORADO DURING
THE AFTN AND EVENING HRS ON THURSDAY. WILL REFLECT THIS IN THIS
MORNING`S FCST PACKAGE. THE CHANCE OF SHOWERS/T-STORMS MAY NOT
END THERE AS MODELS CONTINUE TO INDICATE SCATTERED AREAS OF LIGHT
QPF THU NIGHT THRU FRI NIGHT WITH THE SHORT WAVE TROUGH PASSING
TO OUR NORTH AND WITH A JET STREAM OVERHEAD. THURSDAY TEMPS
EXPECTED TO BE THE WARMEST OF THE WEEK...WITH A FEW DEG COOL DOWN
ON FRIDAY. SAT LOOKS DRIER BASED ON LATEST GUIDANCE ALONG WITH
LITTLE CHANGE IN TEMP.

&&

.AVIATION...(FOR THE TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 425 AM MDT SUN APR 26 2015

LOW CLOUDS WITH PERIODS OF LIGHT RAIN WILL CONTINUE TODAY AND
TONIGHT. EXPECT CEILINGS TO REMAIN LESS THAN 1500 FEET THROUGH TODAY
AND TONIGHT. CEILINGS MAY DROP BELOW 500 AT TIMES AND REDUCE
VISIBILITY TO LESS THAN A MILE. EASTERLY WINDS WILL PREVAIL THROUGH
TONIGHT. GUSTS TO 25 KNOTS WILL BE POSSIBLE OUT OF THE EAST AFTER
16Z.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING FROM NOON TODAY TO NOON MDT MONDAY FOR
COZ033-034.

&&

$$

SHORT TERM...MEIER
LONG TERM...BAKER
AVIATION...MEIER


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