Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 241546
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
946 AM MDT FRI JUL 24 2015

.UPDATE...
ISSUED AT 932 AM MDT FRI JUL 24 2015

SATELLITE SHOWING INCREASING MOISTURE FLOWING IN FROM THE SW AS
THE MONSOON REPOSITIONS ITSELF OVER THE REGION. THIS MOISTURE WILL
SLOWLY ERODE THE DRYER MID LEVEL DECK THROUGH THE DAY ACCORDING TO
THE HRRR AND LATEST NAM THAT COULD LEAD TO SOME RAINSHOWERS MOVING
INTO THE METRO AREA. INCREASED POPS IN ACCORDANCE WITH THIS TREND.
INSTABILITY WILL BE LOW WITH INCREASING CLOUDS THROUGH THE MORNING
INHIBITING HEATING BUT WITH PW VALUES INCREASING CLOSE TO 1 INCH
BY 22Z BRIEF MODERATE TO HEAVIER RAINSHOWERS WILL BE POSSIBLE
UNDER THE STORMS. TEMPERATURES SEEM TO BE ON TRACK TODAY TO HIT
THE LOWER 90S SO DID NOT MAKE ANY ADJUSTMENTS.

&&

.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 422 AM MDT FRI JUL 24 2015

MID AND HIGH LEVEL MOISTURE WILL BE INCREASING FROM THE SOUTH
TODAY. PRECIPITABLE WATER RANGES FROM AROUND A HALF INCH IN THE
NORTHWEST PART OF OUR AREA TO 0.9 INCH AT PUEBLO. AT THE SURFACE
THERE IS A POCKET OF DRY AIR ALONG THE FRONT RANGE WHICH WILL
LIKELY PERSIST WITH LIGHT NORTH WINDS...THOUGH THERE IS BETTER
MOISTURE IN THE NEBRASKA PANHANDLE THAT WILL KEEP IT FROM DRYING
TOO MUCH FURTHER EAST. WITH CONTINUED HOT AIR ALOFT...THE LOW
LEVEL DRYING...AND MORE CLOUD COVER INSTABILITY WILL CONTINUE TO
BE LIMITED TODAY. EXPECT THAT MOST OF OUR ACTIVITY WILL BE DRIVEN
BY THE MID LEVEL MOISTENING GENERATING WEAK THUNDERSTORMS ACROSS
THE SOUTHERN PART OF THE AREA. SOME POTENTIAL FOR STRONGER SURFACE
BASED STORMS IN THE BETTER MOISTURE NEAR THE EASTERN BORDER
AGAIN...CAPES UP TO 1000 J/KG STILL LIMITED BY THE WARMTH ALOFT
THOUGH SO NOT TOO MUCH OF A SEVERE THREAT. ONLY MADE MINOR
ADJUSTMENTS TO THE FORECAST...MORE CLOUD COVER AND SLIGHTLY HIGHER
POPS ACROSS THE SOUTH.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 422 AM MDT FRI JUL 24 2015

THE STRONG UPPER RIDGE ANCHORED OVER TEXAS PAST COUPLE OF DAYS IS
FORECAST TO WEAKEN AND SLIP SOUTHEAST AS A WEAK MID-LEVEL
SHORTWAVE TROUGH EMBEDDED IN SWLY FLOW ALOFT SWEEPS ACRS NERN
COLORADO EARLY ON SATURDAY. PASSAGE OF THIS WAVE APPEARS TO
TEMPORARILY DIVERT THE MONSOON MOISTURE PLUME EASTWARD AWAY FROM
THE FCST AREA ALLOWING DRIER AND WARMER AIR TO SPREAD OVER THE
AREA. WARMING ALOFT TOGETHER WITH FALLING PW VALUES EXPECTED TO
SUPPRESS T-STORM FORMATION EXCEPT PERHAPS OVER SOUTHERN AND
EASTERN FRINGES OF THE FCST AREA WHERE THERE SHOULD STILL BE
ENOUGH LOW-LEVEL MOISTURE AND INSTABILITY AVAILABLE FOR ISOLATED
STORMS. DOWNSLOPE FLOW OFF THE FRONT RANGE SHOULD PROVIDE A
HEALTHY BOOST TO TEMPS ON THE ADJACENT PLAINS SATURDAY MORNING
ONLY TO SEE WARMING SLOW IN THE AFTERNOON WITH A SHIFT TO AN
ANTICYCLONIC UPSLOPE FLOW. ITS THIS REVERSAL IN FLOW THAT WILL
CONCENTRATE LATE DAY CONVECTION ALBEIT LIMITED TO THE PALMER DVD
AND SRN FTHLS. GUSTY MICROBURST WINDS AND LIGHTNING MOST LIKELY
MAIN PRODUCTS OF THIS HIGH BASED CONVECTION. LOOK FOR HIGHS ON
SATURDAY TO BE 3-4DEG C ABOVE AVERAGE.

ON SUNDAY...THE SOUTHERN GREAT PLAINS RIDGE IS FCST TO STRENGTH
WITH AN INFLUX OF MOISTURE AND WARMER AIR FROM THE GULF.
AMPLIFICATION OF THE RIDGE OVER THE CENTRAL PLAINS DRIVES ANOTHER
SURGE OF SUBTROPICAL/MONSOONAL MOISTURE NORTHWARD INTO SRN
COLORADO BY MORNING AND OVER NERN COLORADO BY THE AFTERNOON.
HUMIDITY AND VERTICAL MOTION MODEL CROSS SECTIONS SHOW MID/HIGH
CLOUDS THICKENING FROM SOUTH TO NORTH THROUGH THE DAY WITH MODEST
MID-LEVEL ISENTROPIC UPGLIDE. WHILE UPPER LEVELS MOISTEN...A
S-SWLY BNDRY LAYER FLOW APPEARS TO KEEP THE SUB-CLOUD/BNDRY LAYER
RELATIVELY DRY. EVEN SO...STILL EXPECT TO SEE ISOLATED TO
SCATTERED T-STORMS FORMING OVER SOUTHERN AND SOUTHEASTERN SECTIONS
OF THE CWA BY MID TO LATE AFTERNOON WHERE PW VALUES WILL EXCEED AN
INCH. THERE/S A REMOTE CHANCE THAT A FEW STORMS ON THE E-CNTRL
PLAINS...SUCH AS IN ERN ELBERT AND LINCOLN COUNTIES...COULD
PRODUCE BRIEF HVY RAINFALL AND SMALL HAIL. HIGH TEMPS OF SUNDAY
ONLY A DEG OR TWO COOLER EVEN WITH THE ADDITIONAL CLOUD COVER.

MONDAY-THURSDAY...THE TALL UPPER RIDGE OVER THE GREAT PLAINS IS
PROGGED TO MIGRATE EAST AS A VIGOROUS UPPER TROUGH SWINGS DOWN
ACROSS THE PACIFIC NORTHWEST. SWLY FLOW ALOFT OVER COLORADO
STRENGTHENS SOME ON MONDAY WHICH AIDS IN DRIVING A BIT MORE
SUBTROPICAL MOISTURE UP ACRS SERN SECTIONS OF THE STATE DURING THE
DAY. SOME OF THIS MOISTURE MAINLY AT MID AND HIGH LEVELS WILL
BRUSH THE SERN CORNER OF THE FCST AREA RESULTING IN A SLIGHT
CHANCE OF LATE DAY T-STORMS. MONDAY TEMPS LIKELY TO BE THE
WARMEST READINGS OF THE UPCOMING WEEK WITH MID 90S ON THE
PLAINS...LOWER 80S IN THE MTN VALLEYS AND 60S/70S AT HIGHER
ELEVATIONS. ON TUESDAY...MODELS SHOW THE PAC NW UPPER TROUGH
RACING EAST ALONG THE U.S./CANADIAN BORDER AND AS IT PASSES TO
OUR NORTH...THE GFS AND CANADIAN SHOW AN ACCOMPANYING COLD FRONT
SLIPPING SOUTH ACRS NERN COLORADO EARLY THAT MORNING. WHEREAS THE
ECMWF SHOWS THIS FRONTAL BNDRY ARRIVING ABOUT 6 HRS LATER. THAT
SAID...THIS COOLER POST FRONTAL AIRMASS WILL PROBABLY BE TOO
STABLE FOR STORMS ON THE PLAINS THAT DAY...BUT BY EVENING
MOISTENING UPSLOPE FLOW IS EXPECTED TO PRODUCE ISOLATED TO
SCATTERED SHWRS/T-STORMS OVER AND NEAR THE FRONT RANGE. LOOK FOR
TEMPS ON TUE TO BE SEVERAL DEGREES COOLER WITH HIGHS 3-4DEG C
BELOW AVERAGE. REST OF THE WEEK...MODELS SHOW A DRIER...MORE
STABLE WEST-NORTHWESTERLY FLOW SETTING UP OVER THE REGION AS A
STRONG UPPER RIDGE BUILDS OVER THE INTERMOUNTAIN WEST. RAIN
CHANCES WEDNESDAY AND THURSDAY WILL BE QUITE LOW WITH TEMPS NEAR
TO SLIGHTLY BELOW AVERAGE EACH DAY.

&&

.AVIATION...(FOR THE TAFS THROUGH 18Z SATURDAY MORNING)
ISSUED AT 932 AM MDT FRI JUL 24 2015

VFR EXPECTED FOR THE PERIOD WITH LIGHT TO VARIABLE WINDS THAT
WILL SLOWLY MOVE AROUND TO A NORTHERLY PUSH THIS AFTERNOON BEFORE
TURNING BACK SW AS FLOW INCREASES FROM THAT DIRECTION. ACCORDING
TO LATEST HRRR THE MID LEVEL WARM LAYER WILL START TO ERODE THAT
COULD INTRODUCE SOME RAINSHOWERS INTO THE AIRPORTS. DO NOT EXPECT
VISIBILITY RESTRICTIONS BUT WILL UPDATE AT TAF TIME TO INCLUDE IN
A TEMPO GROUP FOR LATER THIS AFTERNOON. LIGHT GUSTING TO 25 WILL
ALSO BE POSSIBLE.

&&

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

$$

UPDATE...BOWEN
SHORT TERM...GIMMESTAD
LONG TERM...BAKER
AVIATION...BOWEN


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