Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 071657
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
1057 AM MDT MON JUL 7 2014

.UPDATE...
ISSUED AT 1055 AM MDT MON JUL 7 2014

WILL MAKE MINOR ADJUSTMENTS TO SKY COVER...WIND AND TEMPERATURE
GRIDS FOR TODAY. ALSO DELAYED START OF T-STORMS UNTIL LATE THIS
AFTERNOON. NOW APPEARS BULK OF CONVECTION NOT UNTIL EARLY THIS
EVENING...BUT WITH STRONG HEATING...CAN NOT RULE OUT ISOLATED
MAINLY HIGH BASED GUSTY STORMS LATE THIS AFTERNOON. STRONG COLD
FRONT STILL ON THE WAY. 12Z MODEL RUNS INDICATE ARRIVAL OF THE
FRONT IN FAR NERN COLORADO BETWEEN 22Z/MON-00Z/TUE...AND IN THE
DENVER AREA BETWEEN 00Z-02Z. PROBABLY CLOSER TO 01Z SHOULD OUTFLOW
FROM CONVECTION UP IN WY/NE GIVE IT AN EXTRA PUSH. AS FOR HIGHS
TODAY...ALREADY 93 DEGS F AT DIA. TEMPS RUNNING AHEAD OF
YESTERDAY AT THIS TIME. AT THIS PACE COULD SEE A FEW +100 DEG
TEMPERATURES WITHIN THE I-25 CORRIDOR. CURRENT FCST ALREADY HAD A
BATCH OF 100 DEGS MAX TEMPS IN MORGAN COUNTY AND OUT TOWARDS
STERLING. WILL EXPAND THAT TO PORTIONS OF THE URBAN CORRIDOR BASED
ON CURRENT TEMP TREND. RECORD HIGH FOR THE DATE AT DENVER IS 102F.
COULD COME REAL CLOSE SHOULD CLOUDS DELAY LONGER THAN IS NOW
EXPECTED. LASTLY...THE HIGH RES AND NAMNEST SYNTHETIC SATELLITE
IMAGERY INDICATE A BLOWUP OF T-STORMS RIGHT OVER THE DENVER AREA
AROUND MID-EVENING. MODEL CROSS SECTIONS SOMEWHAT SUPPORT SUCH A
DEVELOPMENT WITH FORCING ALOFT AND A DEEPENING MOIST UPSLOPE
FLOW. THEREFORE TO PLAY IT SAFE WILL UP POPS ALONG THE FRONT RANGE
THIS EVENING...SPECIFICALLY OVER SOUTHERN PORTIONS OF THE I-25
URBAN CORRIDOR AND PALMER DIVIDE...TO ACCOUNT FOR THIS
POSSIBILITY. COULD POSSIBLY SEE A FEW STORMS ON THE PLAINS GO
SEVERE THIS EVENING WITH LARGE HAIL MAIN THREAT.

&&

.AVIATION...(FOR THE TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 1055 AM MDT MON JUL 7 2014

CLEAR/MOSTLY CLEAR TODAY WITH NEAR RECORD HEAT AND LOW
HUMIDITIES. HOWEVER LATER THIS AFTERNOON AS SFC WINDS SHIFT FROM
WEST-NORTHWEST TO NORTH-NORTHEAST HUMIDITIES WILL BEGIN TO RISE
AND CONVECTION WILL BEGIN FORMING OVER AND ALONG THE FRONT RANGE.
AFTER 22Z TODAY...COULD SEE A FEW HIGH BASED GUSTY MOSTLY DRY
T-STORMS MOVE OFF THE FOOTHILLS AND OVER THE DENVER AREA PRODUCING
GUSTY AND ERRATIC OUTFLOW WINDS. THEN SHORTLY AFTER 00Z/TUE...
PROBABLY CLOSE TO 01Z...NELY WINDS WILL STRENGTHEN WITH ARRIVAL OF
A STRONG COLD FRONT. THAT/S WHEN CHANCES FOR THUNDERSTORMS IN THE
DENVER AREA WILL RAMP UP. CLOUD BASES WILL LOWER INCREASING THE
CHANCE FOR WETTING RAINFALL. OVERNIGHT...STORMS SHOULD END AROUND
MIDNIGHT...AS CLOUD CEILINGS CONTINUE TO LOWER. COULD SEE MVFR OR
POSSIBLE IFR CIGS AFTER 09Z. ALTHOUGH NO PCPN FROM THIS LOW CLOUD
DECK.

.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 336 AM MDT MON JUL 7 2014

MORE ACTIVE WEATHER IS SETTING UP FOR THE FORECAST AREA...MOSTLY
THIS EVENING. UNTIL THEN...ANOTHER HOT DAY IS IN STORE AS WE ARE
STUCK IN BETWEEN BETTER MONSOONAL MOISTURE TO THE SOUTH AND THE
NORTHERN PLAINS STATES SHORT WAVE. THERE IS REASONABLE AGREEMENT
IN THE SHORT RANGE MODELS SUPPORTED BY WATER VAPOR IMAGERY AND
00Z UPPER AIR PLOTS THAT A DRY SLOT WILL MOVE OVER NORTHERN
COLORADO THROUGH THIS AFTERNOON. THE ONLY PLACES THAT COULD SEE
ISOLATED HIGH BASED STORMS FOR MOST OF THE AFTERNOON WOULD BE THE
FRONT RANGE MOUNTAINS AND FOOTHILLS MAINLY SOUTH OF I-70 AND THE
PALMER DIVIDE AREA ON THE FRINGE OF THE DRIER AIR ALOFT.

THE DRIER AIRMASS ALSO MEANS TEMPERATURES WILL BE WARMER THAN
EARLIER FORECAST. AT THIS TIME...EXPECT HIGH TEMPERATURES JUST AS
HOT OR EVEN A COUPLE DEGREES WARMER THAN YESTERDAY WITH A FEW
SPOTS INCLUDING DENVER REACHING CLOSE TO 100F. FIRE DANGER WILL
INCREASE WITH ANOTHER HOT AND DRY DAY...AND WINDS INCREASING IN
THE NORTHERN MOUNTAINS/HIGH VALLEYS THIS AFTERNOON AND ACROSS THE
NORTHEAST PLAINS WITH FRONTAL PASSAGE. HOWEVER...HUMIDITIES WILL
INCREASE RATHER QUICKLY BEHIND THE FRONT.

BY LATE THIS AFTERNOON...A SIGNIFICANT COLD FRONT WILL PUSH INTO
THE NORTHEAST CORNER OF THE STATE AND THEN SOUTHWARD ACROSS THE
PLAINS VERY LATE THIS AFTERNOON INTO EARLY EVENING. BOTH MOISTURE
AND UPSLOPE COMPONENT WILL INCREASE SHARPLY BEHIND THIS FRONT ON
THE HEELS OF GUSTY NORTHEAST WINDS. GIVEN SOME UNCERTAINTY IN
TIMING...AS THE FRONT IS STILL IN NORTHERN MONTANA EARLY THIS
MORNING...WILL BEGIN A LOW POP MOST AREAS VERY LATE THIS AFTERNOON
BUT HAVE BEST POPS DEVELOPING DURING THE EVENING HOURS. ENOUGH
INSTABILITY MAY BE PRESENT FOR A FEW STRONG TO SEVERE STORMS AS
WELL...WITH STRONGEST CONVECTION LIKELY SHIFTING OR DEVELOPING FROM
THE NORTHEAST PLAINS TO THE FRONT RANGE URBAN CORRIDOR/FOOTHILLS
BY MID/LATE EVENING.

AFTER MIDNIGHT...AIRMASS GRADUALLY STABILIZES WITH A STRATUS DECK
LIKELY DEVELOPING IN THE COOL/MOIST UPSLOPE REGIME.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 336 AM MDT MON JUL 7 2014

IT CONTINUES TO LOOK LIKE TUESDAY WILL BE THE FIRST DAY OF THE
MONSOON SEASON FOR THE STATE OF COLORADO. THE UPPER RIDGE THAT IS
IN PLACE OVER THE GREAT BASIN AND SOUTHWEST U.S. THIS MORNING WILL
REMAIN IN PLACE THROUGH THE REMAINDER OF THE WEEK...SETTING UP A
PATTERN OF MOIST EASTERLY FLOW ALOFT ACROSS NEW MEXICO AND ARIZONA
AND THEN MODEST NORTHWESTERLY FLOW OVER COLORADO. MOISTURE THAT
GETS DRAWN OVER THE DESERT SOUTHWEST WILL EVENTUALLY MAKE ITS WAY
OVER COLORADO TO FUEL THE DEVELOPMENT OF AFTERNOON AND EVENING
THUNDERSTORM ACTIVITY. MID- AND LONG-RANGE MODELS ARE ALL
CONSISTENT IN PRODUCING RAINFALL OVER THE MOUNTAINS AND PLAINS
EACH DAY THROUGH NEXT SUNDAY. THE PATTERN LOOKS VERY PLAUSIBLE
SINCE EACH OF THE MODELS ARE DEPICTING A SIMILAR SOLUTION...AND
CLIMATOLOGY WOULD FAVOR THE ONSET OF THE MONSOONAL PATTERN AT SOME
POINT BY MID-JULY. AFTER A RELATIVELY COOL DAY ON TUESDAY...IN THE
WAKE OF TONIGHTS STRONG FRONTAL PASSAGE...THE REST OF THE WEEK
WILL SEE TEMPERATURES REBOUND TO SEASONAL NORMALS...AND VERY MILD
OVERNIGHT MINIMUMS. THE FORECAST WILL ALSO FEATURE PRETTY HEALTHY
CHANCES OF PRECIPITATION EACH AFTERNOON AND EVENING.

ALONG WITH THE MONSOONAL FLOW PATTERN...WILL COME THE THREAT OF
HEAVY RAIN FROM SLOW MOVING THUNDERSTORMS WITHIN THE MOIST
AIRMASS. IF WE START SEEING AREAS RECEIVE HEALTHY AMOUNTS OF
PRECIPITATION THEN FLASH FLOOD WATCHES MAY BECOME NECESSARY AT
SOME POINT. BUT FOR NOW...WE WILL JUST BE WATCHING OUT FOR THE
AREAS THAT GET ANY HEAVY RAIN. NO HYDROLOGY HIGHLIGHTS AT THIS
TIME.

&&

.AVIATION...(FOR THE TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 336 AM MDT MON JUL 7 2014

VFR CONDITIONS WILL PERSIST THROUGH 00Z. THERE IS JUST A SLIGHT
CHANCE OF A STORM DEVELOPING 23Z-01Z...WITH SCATTERED STORMS
EXPECTED 01Z-05Z BEHIND THE PASSAGE OF A STRONG COLD FRONT FOR
THIS TIME OF YEAR. A FEW OF THOSE STORMS COULD BE STRONG WITH
SOME HAIL. NORTHEAST WINDS WILL LIKELY GUST TO AROUND 30 KTS WITH
FRONTAL PASSAGE NOW LOOKING AROUND 00Z-01Z. CEILINGS EXPECTED TO
LOWER WITH ILS LANDING CONDITIONS LIKELY DEVELOPING BY 06Z-09Z AND
POTENTIAL FOR MVFR CEILINGS. THE LOWER CLOUDS SHOULD LINGER
THROUGH MUCH OF TUESDAY MORNING BEFORE GRADUALLY LIFTING.


&&

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

$$

UPDATE...BAKER
SHORT TERM...BARJENBRUCH
LONG TERM...DANKERS
AVIATION...BARJENBRUCH



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