Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 250943
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
343 AM MDT SAT JUL 25 2015

.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 340 AM MDT SAT JUL 25 2015

UPPER LEVEL HIGH WILL REMAIN CENTERED OVER TEXAS THROUGH TONIGHT.
THIS WILL KEEP A SOUTHWEST FLOW ALOFT OVER COLORADO. THE MONSOON
MOISTURE THAT PASSED OVER THE STATE YESTERDAY WILL SHIFT SOUTH AND
EAST. THIS WILL BE REPLACED BY DRIER AIR WITH PRECIPITABLE WATER
VALUES FALLING TO SIX TO EIGHT TENTHS INCH RANGE. THE DRIEST AIR
WILL BE WEST AND NORTH AND JUST EXPECT FAIR WEATHER CUMULUS DURING
THE AFTERNOON. COULD SEE A COUPLE AFTERNOON AND EARLY EVENING
THUNDERSTORMS OVER SOUTHERN AND EASTERN SECTIONS OF THE AREA. CAPES
WILL BE LESS THAN 500 J/KG SO STORMS SHOULD NOT BE SEVERE. HIGHS
WILL BE WARMER TODAY DUE TO LESS CLOUD COVER WITH HIGHS CLIMBING
INTO THE 90S.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 340 AM MDT SAT JUL 25 2015

BY SUNDAY...THE STRONG UPPER RIDGE ANCHORED OVER THE SOUTHERN GREAT
PLAINS IS FORECAST TO EXPAND NORTHWARD AND AS IT DOES A PLUME OF
SUBTROPICAL MOISTURE IS DRAWN NORTHEASTWARD ACRS NEW MEXICO INTO
COLORADO DURING THE DAY. APPEARS THE LEADING EDGE OF THIS MAINLY MID
AND HIGH-LEVEL MOISTURE REACHES SRN COLORADO BY MORNING AND NERN
COLORADO BY AFTERNOON. EARLIER IT APPEARED AS THOUGH S-SWLY BNDRY
LAYER FLOW WOULD KEEP THE SUB-CLOUD/BNDRY LAYER OVER THE PLAINS
GENERALLY RAIN FREE. NOW MODELS ARE INDICATING A SELY LOW-LEVEL FLOW
WHICH WOULD ADVECT IN HIGHER DEWPOINTS. AFTERNOON TEMPS IN THE UPPER
80S/LOWER 90S AND PW VALUES IN THE 1 TO 1.25 INCH RANGE GENERATE 0-
3KM CAPE VALUES IN THE 1000-1800 J/KG RANGE ALONG THE PALMER DIVIDE
OUT ACROSS ELBERT AND LINCOLN COUNTIES. AND WITH SELY SFC WINDS
STRENGTHENING DURING THE AFTERNOON RESULTING IN VERTICAL SHEAR
PROFILES SUPPORTING A FEW T-STORMS CAPABLE OF LARGE HAIL AND HEAVY
RAINFALL. NAM AND ECMWF INDICATE THE FORMATION OF A SFC BASED
CYCLONE JUST EAST OF THE DENVER METRO AREA WHICH COULD SPIN-UP A FEW
STRONG STORMS IN THE AREA BY LATE AFTERNOON. MUCH DEPENDS ON WHEN
THE THICKER CLOUD COVER ARRIVALS. TOO EARLY...STORMS MAY NOT GET OFF
THE GROUND. FOR THESE REASONS WILL RAISE POPS ACROSS THE SERN
QUADRANT OF THE FCST AREA SUNDAY AFTERNOON AND EARLY EVENING AND
WELL AS GO WITH 30-50 PCT POPS IN MTN AND FTHL AREAS SOUTH OF I-70.
NORTHERN SECTIONS OF THE CWA MAY ESCAPE WITH ONLY ISOLATED SHOWERS/T-
STORMS AS THE AIR WILL BE DRIER AND LESS UNSTABLE IN THESE AREA.
EXPECTING HIGHS ON SUNDAY TO BE ONLY A DEG OR TWO COOLER THAN THOSE
ON SATURDAY EVEN WITH ALL OF THE CLOUD COVER.

BY MONDAY...THE UPPER RIDGE HAS MOVED LITTLE AND THE SUBTROPICAL
MOISTURE PLUME IS STILL OVER SRN AND ERN SECTIONS OF COLORADO.
ALTHOUGH THROUGH THE DAY THIS PLUME IS FORECAST TO THIN OUT ONCE A
WEAK MID-LEVEL SHORTWAVE DISTURBANCE LIFTS NEWRD ACRS THE STATE.
LOWER BNDRY LAYER MOISTURE AND MEAN LAYER PW VALUES MAKE IT LESS
LIKELY WE`LL SEE ANY SEVERE WX...EXCEPT PERHAPS THE FAR NORTHEAST
CORNER OF THE STATE WHERE FAVORABLE SHEAR...STEEP MID-LEVEL LAPSE
RATES AND CAPES POTENTIALLY IN THE 1000-2000 J/KG AHEAD OF THE
SHORTWAVE COULD GENERATE A FEW SEVERE STORMS DURING THE AFTERNOON.
HOWEVER THE HIGHER PRECIP CHANCES ARE BELIEVED TO REMAIN OVER SERN
SECTIONS OF THE CWA BENEATH THE CORE OF THE MOISTURE PLUME. AS FOR
TEMPS...DEVELOPMENT OF GUSTY SWLY WINDS IN THE WAKE OF THE UPPER
TROUGH SHOULD SEND TEMPS INTO THE LOW/MID 90S ON THE PLAINS MAKING
MONDAY THE WARMEST DAY DURING THE UPCOMING WEEK.

ON TUESDAY...THE UPPER RIDGE OVER THE GREAT PLAINS MIGRATES EAST AS
A VIGOROUS SHORTWAVE TROUGH SWINGS OUT OF THE PACIFIC NORTHWEST AND
OVER THE NORTHERN ROCKY MTN REGION. GFS AND CANADIAN MODELS SHOW A
STRONG COLD FRONT AT THE BOTTOM OF THIS TROUGH SLIPPING ACROSS
WYOMING LATE ON TUESDAY AND DROPPING INTO NENR COLORADO TUESDAY
NIGHT. THIS FRONTAL SYSTEM APPEARS TO LOSE MUCH OF THIS MOMENTUM AND
COLD AIR BY THE TIME ITS REACHES COLORADO...HOWEVER SHALLOW MOISTURE
AND COLD AIR ADVECTION WITH UPSLOPE FLOW MAY PRODUCE A DECK OF
STRATUS AND PERHAPS SOME FOG UP AGAINST THE FRONT RANGE LATE TUESDAY
NIGHT INTO WEDNESDAY MORNING. HIGHS ON TUESDAY SEVERAL DEGS COOLER
THAN THE DAY BEFORE DUE IN PART TO COOLING ALOFT WITH HIGHS 2-3
DEGS C BELOW AVERAGE.

ON WEDNESDAY...NELY LOW-LEVEL FLOW EAST OF THE MTNS CONTINUES TO
COOL SFC TEMPS WHILE COLD AIR ADVECTION CONTINUES ALOFT WITH NWLY
POST-TROUGH FLOW UP HIGH. TEMPS ON WEDNESDAY MOST LIKELY COOLEST
READINGS OF THE WEEK WITH UPPER 70S/LOWER 80S ON THE PLAINS. ANY
CHANCE OF PRECIP WILL COME LATE IN THE DAY OVER AND NEAR THE FRONT
RANGE AND PALMER DIVIDE WHERE THE CAPPING FRONTAL INVERSION WILL BE
WEAKEST.

THURSDAY AND FRIDAY...MEDIUM RANGE MODELS SHOW A DRIER...MORE STABLE
WEST-NORTHWESTERLY FLOW OVER THE REGION AS A STRONG UPPER RIDGE
BUILDS OVER THE INTERMOUNTAIN WEST. RAIN CHANCES APPEAR QUITE LOW
WITH TEMPS NEAR TO SLIGHTLY BELOW AVERAGE EACH DAY.&&

.AVIATION...(FOR THE TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 340 AM MDT SAT JUL 25 2015

VFR CONDITIONS WILL PREVAIL THE NEXT 24 HOURS. SOUTHERLY WINDS WILL
LINGER THROUGH THE MID MORNING HOURS...ABOUT 15Z. WINDS WILL BECOME
LIGHT AND END UP EASTERLY AFTER 18Z. AIRMASS WILL REMAIN DRY
TODAY...SO NO THUNDERSTORMS ARE EXPECTED TODAY OR TONIGHT.

&&

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

$$

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


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