Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 062126
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
326 PM MDT WED MAY 6 2015

.SHORT TERM...(THIS EVENING THROUGH THURSDAY)
ISSUED AT 326 PM MDT WED MAY 6 2015

WRAPAROUND SHOWER BAND CONTINUES TO DRIFT EAST ACROSS THE
NORTHEAST CORNER OF COLORADO...WHILE NUMEROUS SHOWERS AND STORMS
HAVE FORMED ON THE WARM SIDE OF THE BACK EDGE DEFORMATION FROM
WESTERN INTO CENTRAL COLORADO. DENVER IS IN BETWEEN THESE TWO
AREAS FOR NOW...BUT EXPECT THE PATTERN TO CONTINUE TO SHIFT SLOWLY
EAST AND THAT COMBINED WITH MORE HEATING SHOULD HELP FILL IN THE
SHOWER ACTIVITY LATER THIS AFTERNOON. BIGGEST RISK FOR HEAVY
RAIN/SMALL HAIL/GUSTY WINDS SHOULD BE ON THE SOUTH FRINGE OF OUR
AREA WHERE IT IS WARMER AND MORE UNSTABLE. WITH THE CLOUD COVER
OVER THE MOUNTAINS...THIS WILL PROBABLY JUST WIND UP BEING ELBERT
AND LINCOLN COUNTIES.

NOT SURE HOW MUCH CLEARING THERE WILL BE OVERNIGHT AND RESULTING
FOG FORECAST. WITH LIGHT WINDS...CONTINUING WEAK CONVECTION THIS
EVENING...AND LACK OF STRONG SUBSIDENCE I SUSPECT THERE WILL STILL
BE PLENTY OF HIGHER LEVEL CLOUDS. HOW MUCH STRATUS REDEVELOPS WILL
LIKELY DEPEND ON THE AMOUNT OF RAIN ALONG WITH SOME CLEARING. LEFT
THE MOSTLY CLOUDY SKIES AND AREAS OF FOG...BUT IT MAY JUST TURN
OUT TO BE THE HIGHER CLOUDS GRADUALLY CLEARING IN THE EARLY
MORNING HOURS.

FOR THURSDAY THE ENVIRONMENT WILL BE A LITTLE DRIER...BUT THERE
WILL BE A BIT MORE INSTABILITY IN THE AFTERNOON. WE SHOULD HAVE
LOWER COVERAGE OF SHOWERS. THERE COULD BE MORE INTENSITY
THOUGH...STILL PROBABLY LOOKING AT 300-700 J/KG OF CAPE. NOT MUCH
OF A SEVERE THREAT BUT MAYBE MORE STORMS THAN SHOWERS.

.LONG TERM...(THURSDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 326 PM MDT WED MAY 6 2015

SHOWERS AND A FEW THUNDERSTORMS WILL CONTINUE INTO THURSDAY
EVENING. A COLD FRONT IS EXPECTED TO PUSH INTO THE FRONT RANGE
LATE THURSDAY NIGHT INTO FRIDAY MORNING. SHOULD SEE LIGHT MODERATE
RAINFALL THURSDAY EVENING...THEN THE MID LEVELS DRY OUT OVERNIGHT
WITH LOW LEVEL MOISTURE INCREASING BELOW 700 MB FOLLOWING THE
PASSAGE OF THE COLD FRONT. AS A RESULT...A MIX OF LIGHT RAIN OR
DRIZZLE WILL OCCUR IN THE MORNING. FRIDAY AFTERNOON AND FRIDAY
NIGHT...THE NEXT SYSTEM WILL BE OVER CENTRAL CALIFORNIA WITH A
WEAK BUT DIFLUENT SOUTHWESTERLY FLOW ALOFT OVER COLORADO. ELEVATED
CONVECTION WILL DEVELOP OVER THE MOUNTAINS IN THE AFTERNOON...THEN
SPREAD EASTWARD INTO THE NORTHEAST PLAINS BY LATE AFTERNOON AND
EVENING. SNOW LEVELS REMAIN RELATIVELY HIGH FRIDAY AFTERNOON...AOA
10500 FEET...BUT DROP TO AROUND 8500 FEET BY 12Z SATURDAY MORNING.

WEATHER GETS MORE COMPLEX OVER THE WEEKEND...LATE FRIDAY NIGHT AND
SATURDAY...THE CLOSED LOW WILL BE OVER SWRN UT BY 06Z FRIDAY
NIGHT...AND WILL MOVE SOUTHWESTERN CO BY 18Z SATURDAY...WITH A 90+
KT JET MAX ROUNDING THE TROUGH AND MOVING ACROSS EASTERN NEW
MEX/EASTERN COLORADO. THE AIRMASS WILL BECOME INCREASINGLY MOIST
AND UNSTABLE THROUGH THE DAY SATURDAY AS THE TROUGH CONTINUES TO
TRACK NORTHEAST ACROSS THE STATE. MODERATE TO STRONG QG ASCENT
WILL BE OVER THE CWA SATURDAY AFTERNOON AND EVENING.

BY 00Z SUNDAY...THE CLOSED UPPER LOW WILL BE NEARLY CENTERED OVER
THE SURFACE LOW AS IT MOVES OVER SOUTHEASTERN COLORADO. THIS WILL
ALLOW FOR A STRONG AND DEEP EASTERLY FLOW AT THE SFC AND ALOFT TO
DEVELOP...STRONGEST OVER SOUTHERN WYOMING AND NORTHERN COLORADO.
GULF MOISTURE WILL GET WRAPPED INTO THE SYSTEM AND ADVECTED INTO
NORTHEASTERN CO...WITH THE POTENTIAL FOR HEAVY SNOW IN PRIMARILY
THE MOUNTAINS AND FOOTHILLS OF LARIMER COUNTY...ZONES 33 AND 35.
THE SNOW LEVEL SATURDAY EVENING WILL BE AROUND 8000 FEET...
DROPPING TO 5500-6000 FEET ALONG THE NORTHERN BORDER TO 7000 FEET
OVER THE SRN PART OF THE CWA BY 12Z SUNDAY. WILL HAVE TO WATCH
LARIMER COUNTY CLOSELY SATURDAY AFTN/EVNG FOR THE POTENTIAL OF
HEAVY RAIN...THE THREAT WILL DECREASE SOMEWHAT AS THE SNOW LEVEL
LOWERS. A WINTER STORM WATCH WILL NOT BE OUT OF THE QUESTION FOR
ZONE 33 AND 35...SATURDAY AFTN INTO SUNDAY MORNING. DEEP UPSLOPE
WITH EMBEDDED TSTMS COULD PRODUCE PERIODS OF HEAVY SNOW IN THOSE
AREAS. SINCE THE WIND PROFILE WILL BE STRONGLY SHEARED WITH STRONG
QG ASCENT IN THE AFTN... COULD SEE SEE AN ISOLATED SEVERE TSTM OR
TWO OVER PARTS OF THE PLAINS. COULD SEE SOME SORT OF DRYLINE
DEVELOP OFF THE PALMER DIVIDE WITH MUCH DRIER AIR LOW LEVEL AIR TO
THE SOUTH. SUNDAY MORNING...THE UPPER LOW AND SFC LOW WILL BE
LOCATED NEAR THE CO/NB/KS BORDERS. STRONG NWLY WINDS WITH WRAP
AROUND MOISTURE AND MUCH COLDER AIR DEVELOPING ON THE BACKSIDE OF
THE SYSTEM. AREAS ALONG THE CHEYENNE/NEBRASKA BORDERS COULD BE
DEALING WITH STRONG WINDS/SNOW AT LEAST THROUGH SUNDAY MORNING.
DEPENDING ON HOW MUCH COLD AIR SPREADS INTO NRN CO...COULD SEE
EITHER A WINTER WEATHER HIGHLIGHT FOR SNOW/BLOWING SNOW OR BRIEF
BLIZZARD CRITERIA. TOO EARLY AND TOO MUCH UNCERTAINTY AT THIS
POINT BUT WILL NEED TO KEEP A CLOSE EYE ON IT. OVERALL PCPN
AMOUNTS THROUGH THE WEEKEND OF 1-2 INCHES POSSIBLE. SUNDAY
AFTN/EVENING THE SYSTEM WILL SHIFT FAIRLY QUICKLY TO THE NORTH AND
EAST WITH A DRIER NORTHWESTERLY FLOW IN ITS PLACE. SHOWERS SHOULD
COME TO AN END OVER THE SRN PART OF THE CWA BUT LINGERING SNOW
SHOWERS IN THE MOUNTAINS WITH A MIX OF RAIN/SNOW SHOWERS OVER THE
FAR NORTHEAST PLAINS. WL CONTINUE TO KEEP THE DRYING TREND IN THE
FORECAST FOR THE EARLY PART OF NEXT WEEK WITH AN UPPER LEVEL RIDGE
OF HIGH PRESSURE MOVING INTO AND BUILDING OVER THE STATE.

&&

.AVIATION...(FOR THE TAFS THROUGH 00Z THURSDAY LATE AFTERNOON)
ISSUED AT 326 PM MDT WED MAY 6 2015

DENVER IS IN A HOLE SURROUNDED BY SHOWERS...STILL EXPECTING MVFR
CONDITIONS TO DEVELOP BY EARLY EVENING AS SHOWERS BECOME MORE
WIDESPREAD. SOME QUESTION ABOUT HOW MUCH CLEARING THERE WILL BE
OVERNIGHT...IF IT DOES CLEAR IT WOULD LEAD TO LOW CLOUDS AND FOG.
AT THIS POINT IT LOOKS LIKE THERE SHOULD BE AREAS OF IFR CEILINGS
BUT THE PROBABILITY OF DENSE FOG LOOKS LOW. SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED THURSDAY AFTERNOON WITH MVFR CONDITIONS
AND GUSTY WINDS POSSIBLE.

&&

.HYDROLOGY...
ISSUED AT 326 PM MDT WED MAY 6 2015

LIGHT TO MODERATE RAIN SHOWERS ARE EXPECTED ACROSS MUCH OF THE
AREA THIS EVENING...THE THREAT OF HEAVY RAIN WILL BE MAINLY IN
ELBERT AND LINCOLN COUNTIES WHERE THERE WILL BE SOME
THUNDERSTORMS. HOWEVER THE STORMS WILL BE MOVING...SO THE THREAT
OF FLOODING TONIGHT APPEARS TO BE LOW.

SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED THURSDAY...AND
WILL BE MORE NUMEROUS ON FRIDAY. HOWEVER THE OVERALL THREAT FOR
FLASH FLOODING WILL REMAIN LOW. THE STRONGEST STORMS COULD
PRODUCE SOME MINOR FLOODING.

THE NEXT SYSTEM WILL MOVE ACROSS COLORADO OVER THE WEEKEND...WITH
THE HEAVIEST PRECIPITATION DEVELOPING SATURDAY AFTERNOON AND
SATURDAY NIGHT. PRECIPITATION WILL BE WIDESPREAD WITH THE PRIMARY
FOCUS AT THAT TIME IN THE MOUNTAINS AND FOOTHILLS OF LARIMER
COUNTY. THE SNOW LEVEL WILL BE AROUND 950O FEET SATURDAY
AFTERNOON...8000 FEET BY SATURDAY EVENING THEN DOWN TO POSSIBLE
5500 FEET BY 12Z SUNDAY. THE THREAT FOR HEAVY RAIN FOR LARIMER
COUNTY WILL OCCUR SATURDAY AFTERNOON INTO SATURDAY EVENING...SO
RIVER LEVELS IN MAY BE ELEVATED IN THE CACHE LA POUDRE DRAINAGE
BASIN. ONCE THE RAIN CHANGES TO SNOW...RUNOFF SHOULD DIMINISH.
FURTHER SOUTH IN THE FOOTHILLS THERE MAY BE A PERIOD OF STEADY
RAIN FRIDAY NIGHT INTO SATURDAY...BUT RAIN AMOUNTS SHOULD BE LESS
THAN THEY WILL BE NEAR THE NORTHERN COLORADO BORDER.

&&

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

$$

SHORT TERM...GIMMESTAD
LONG TERM...COOPER
AVIATION...GIMMESTAD
HYDROLOGY...GIMMESTAD/COOPER



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