Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 070240
AFDBOU

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

.UPDATE...
ISSUED AT 819 PM MDT WED MAY 6 2015

STILL QUITE A BIT OF SHOWERS AND STORMS OVER NORTHERN SECTIONS OF
CWA...ESPECIALLY ACROSS LARIMER...WELD AND MORGAN COUNTIES. LOOKS
LIKE SOME SHALLOW NORTH TO NORTHEAST WINDS MOVING SOUTH OUT OF THE
CONVECTION AND DEVELOPING OVER THE URBAN CORRIDOR. THIS MAY KEEP
SOME SHOWERS TO REDEVELOP AND CONTINUE THROUGH MIDNIGHT. WATER
VAPOR IMAGERY ALSO SHOWING A WEAK WAVE OVER SOUTHWEST COLORADO
WHICH WILL HELP IN AIDING SHOWERS WITH SOME WEAK ASCENT OVERNIGHT.
NOT MANY CHANGES TO UPCOMING ZONE PACKAGE WITH JUST A SLOW AND
GRADUAL DIMINISHMENT OF SHOWERS AND REDUCE SHOWER COVERAGE IN
SOUTHERN PORTION OF CWA. CERTAINLY COULD BE SOME FOG THAT
DEVELOPS AND PENDS ON HOW MUCH CLEARING TAKES PLACE. BASED ON
CURRENT TRENDS WOULD EXPECT ONLY PARTIAL CLEARING LATER IN THE
NIGHT.

&&

.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 06Z THURSDAY EVENING)
ISSUED AT 819 PM MDT WED MAY 6 2015

STRONGEST STORMS JUST MOVING EAST OF KDEN WITH ONLY ISOLATED
SHOWERS BEHIND THIS CONVECTION. HOWEVER WITH WEAK UPSLOPE FLOW
WOULD EXPECT SOME LIGHT SHOWERS SCATTERED OVER THE AREA AT LEAST
THROUGH MIDNIGHT. NOT SURE ON THE FOG DEVELOPMENT LATER TONIGHT
BUT GIVEN THE LINGERING CLOUD COVER...THAT THE FOG WOULD NOT BE AS
DENSE AS NOTED.

&&

.HYDROLOGY...
ISSUED AT 819 PM MDT WED MAY 6 2015

STORMS THAT HAVE DEVELOPED HAVE CERTAINLY BE EFFICIENT RAINFALL PRODUCERS
WITH RAINFALL RATES OF A HALF INCH IN 30 MINUTES OR LESS WITH THE
STRONGER STORMS. HEAVIEST RAIN CONTINUES OVER PORTIONS OF LARIMER
AND WELD COUNTIES AND CONTINUE WITH FLOOD ADVISORIES OVER PORTIONS
OF WELD AND MORGAN COUNTIES. WATCHING THE SOUTH PLATTE AT KERSEY
CLOSELY AS IT HAS BUMPED UP TO ACTION STAGE AND EXPECT SOME
ADDITIONAL WATER INTO THE RIVER FROM EVENING CONVECTION. REMAINDER
OF CWA HAS DRIED OUT IN TERMS OF EVENING CONVECTION BUT STILL
EXPECT SOME SPOTTY SHOWERS OVERNIGHT WITH WEAK WAVE NOW INTO
SOUTHWEST COLORADO.

&&

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

$$

UPDATE...ENTREKIN
SHORT TERM...GIMMESTAD
LONG TERM...COOPER
AVIATION...RJK
HYDROLOGY...ENTREKIN


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