Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 020954
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
354 AM MDT SAT MAY 2 2015

.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 354 AM MDT SAT MAY 2 2015

A FLAT UPPER RIDGE WILL BE ALOFT THROUGH TONIGHT AS A SURFACE
TROUGH FROM EASTERN MONTANA EXTENDS DOWN ALONG THE
COLORADO/KANSAS BORDER AND DEEPENS. HIGH MOISTURE VALUES FROM LAST
EVENINGS STORMS HAVE HELPED SOME PATCHY FOG DEVELOP OVER THE
PLAINS EARLY THIS MORNING...MAINLY ALONG THE SOUTH PLATTE RIVER
VALLEY. THERE COULD BE SOME INCHING INTO EASTERN LINCOLN
COUNTY...BUT ALL THE FOG SHOULD DISSIPATE BY MID MORNING.

THE DEEPENING LOW WILL TURN SURFACE WINDS TO A MORE
SOUTHWEST/WESTERLY DIRECTION TODAY...BRINGING IN DRIER AND WARMER
AIR. THIS WILL ALLOW FOR A MORE NORMAL AFTERNOON CONVECTION START
TIME COMPARED TO YESTERDAYS UPSLOPE INDUCED EARLIER SHOW. PW
VALUES WILL HAVE DECREASED BY AT LEAST 0.2" TODAY FROM YESTERDAY
AND SHEAR WILL BE SLIGHTLY LESS...THEREFORE EXPECT SHOWERS AND
STORMS TO BE MORE OF THE LIGHT RAIN AND GUSTY WINDS TYPE. HOWEVER
WITH MAX TEMPERATURES OVER THE PLAINS ABOUT 10 TO 15 DEGREES
WARMER THAN YESTERDAY...ENOUGH CAPE COULD ALLOW FOR SMALL HAIL.
WHERE THE SURFACE TROUGH AXIS SETS UP WILL DETERMINE THE CHANCE
FOR STRONGER/WETTER STORMS OVER THE EAST PLAINS. MOISTURE MAY HOLD
IN LONG ENOUGH INTO THE AFTERNOON FOR STRONGER STORMS CONTAINING
POSSIBLE INCH OR SLIGHTLY LARGER IN DIAMETER HAIL...HOWEVER
LOOKING AT FORECAST SOUNDINGS...LOOKS LIKE THE AXIS WILL PUSH INTO
KANSAS LEAVING DRIER LOWER LEVELS. THESE STORMS COULD STILL
APPROACH SEVERE LEVELS WITH STRONG OUTFLOWS.

CONVECTIVE ACTIVITY WILL PUSH EAST AND DECREASE TONIGHT. EXPECT
SLIGHTLY WARMER MINIMUM TEMPS WITH SLIGHT DOWNSLOPING PATTERN. THE
CIRA WRF SIMULATED SATELLITE SHOWS SOME WAVE CLOUDS FORMING AFTER
MIDNIGHT WHICH WILL KEEP THE FOOTHILLS AND WESTERN METRO AREAS
SLIGHTLY WARMER. THIS IS ALREADY REFLECTED IN THE FORECAST.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 354 AM MDT SAT MAY 2 2015

AN ACTIVE WEATHER PATTERN WILL REMAIN IN PLACE THROUGH MUCH OF
NEXT WEEK WITH DAILY ROUNDS OF SHOWERS AND STORMS.

ON SUNDAY...A FAST MOVING SHORT WAVE OVER THE NORTHERN U.S. WILL
PUSH A COLD FRONT SOUTHWARD ACROSS THE PLAINS BY AFTERNOON. LOW
LEVEL MOISTURE WILL PUSH BACK ACROSS THE PLAINS AND INTO THE FRONT
RANGE DURING THE AFTERNOON AND EVENING HOURS. Q-G FIELDS ALSO SHOW
WEAK LIFT SO EXPECT PRETTY GOOD SHOWER AND STORM COVERAGE DURING
THE AFTERNOON AND EVENING. STORMS COULD ATTEMPT TO ORGANIZE INTO A
MESOSCALE CONVECTIVE COMPLEX ON THE NORTHEAST PLAINS BY EVENING
WITH SUFFICIENT INFLOW OF MOIST LOW LEVEL AIR AND FAVORABLE
SYNOPTIC ENVIRONMENT. LOCALLY HEAVY RAINFALL WOULD BE POSSIBLE ON
THE NORTHEAST PLAINS...BUT SEVERE THREAT IS ONCE AGAIN LIMITED BY
MARGINAL SHEAR AND INSTABILITY. CAPES WILL BE MAINLY IN THE
500-1000 J/KG RANGE WITH ONLY AN ISOLATED SEVERE STORM WITH
MARGINAL HAIL POSSIBLE.

BY MONDAY...THE COOLER AND MORE MOIST AIRMASS WILL HAVE PUSHED
ACROSS ALL OF THE PLAINS. AS A RESULT...THE THREAT OF SHOWERS AND
STORMS MAY DECREASE A BIT. HOWEVER...THERE IS STILL FAVORABLE WEAK
SYNOPTIC SCALE LIFT TO WORK WITH SO SHOULD STILL SEE SHOWERS AND
STORMS DEVELOP IN THE MOUNTAINS AND EVENTUALLY SPREAD NORTHEAST
ACROSS THE PLAINS BY LATE AFTERNOON OR EVENING. IF STORMS
DEVELOP...COULD SEE LOCALLY HEAVY RAINFALL AS PRECIPITABLE WATER
VALUES INCREASE TO AROUND 0.75 INCH ON THE PLAINS...AND A SKINNY
CAPE PROFILE DEVELOPS WITH NEARLY MOIST ADIABATIC LAPSE RATES.
WILL COOL TEMPERATURES OFF SEVERAL DEGREES FROM PREVIOUS FORECAST
GIVEN THE WELL ESTABLISHED COOL AIRMASS AND AREAS OF STRATUS/LOW
CLOUDS THROUGH THE DAY.

TUESDAY IS STILL SHAPING UP TO BE THE MOST ACTIVE WEATHER DAY AS
AN UPPER LEVEL TROUGH OVER THE DESERT SOUTHWEST GETS KICKED
NORTHEAST ACROSS COLORADO. THIS WILL LIKELY BRING MORE WIDESPREAD
SHOWERS AND THUNDERSTORMS TO THE FORECAST AREA. PRECIPITABLE WATER
VALUES ARE EXPECTED TO INCREASE FURTHER WITH DEEP AND MOIST
SOUTH/SOUTHEAST FLOW AHEAD OF TROUGH AXIS...WITH VALUES OF 0.80 TO
AS MUCH AS 1 INCH ON THE FAR EASTERN PLAINS. THOSE VALUES ARE
APPROACHING 2-3 STANDARDIZED ANOMALIES SO DEPENDING ON SPEED OF
EJECTING TROUGH THIS DAY WOULD BE MOST FAVORED FOR HEAVY RAINFALL.
THERE IS A LITTLE GREATER RISK OF A FEW SEVERE STORMS ALTHOUGH
INSTABILITY STILL LOOKS LIMITED AT THIS POINT. WILL CONTINUE TO
WATCH THIS OVER THE NEXT COUPLE DAYS.

BY WEDNESDAY...THE EJECTING SHORT WAVE ENERGY SHOULD CONTINUE TO
PUSH NORTHEAST INTO THE NORTHERN PLAINS STATES. THAT WOULD LEAD
TO LESS SHOWER AND STORM COVERAGE INTO THURSDAY. THEN ANOTHER
ROUND OF MORE ACTIVE WEATHER WITH MORE SHOWERS AND STORMS
BY FRIDAY...ALL DEPENDING ON EVENTUAL LOCATION AND SPEED OF NEXT
DIGGING TROUGH INTO THE SOUTHWEST.

&&

.AVIATION...(FOR THE TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 354 AM MDT SAT MAY 2 2015

SOME PATCHY FOG POSSIBLE OVER WELD AND EASTERN LARIMER COUNTIES WHICH
COULD AFFECT KGXY AND KFNL TIL 15Z. A LOW LEVEL JET OF SOUTH-
SOUTHWESTERLIES ARE PASSING OVER THE PALMER DIVIDE AND TOWARD THE
NE/WY BORDERS...AS EVIDENCED ON THE VAD WIND PROFILE. PLATTEVILLE
PROFILER NOT SHOWING THESE...JET MUST BE JUST TO THE EAST. THIS
MAY KEEP KDEN AND KAPA WINDS ENHANCED FOR THE NEXT HOUR OR
TWO...BUT THERE DOES SEEM TO BE A DECREASE IN SPEEDS ACCORDING TO
THE KFTG RADAR VELOCITIES. AS A SURFACE TROUGH DEEPENS ALONG THE
EASTERN PLAINS...THIS WILL TURN WINDS CLOCKWISE TO THE WEST THEN
NORTHWEST THROUGH THE DAY. AFTERNOON CONVECTION MOVING OFF THE
HILLS WILL BE MORE OF THE LIGHT RAIN AND GUSTY OUTFLOW TYPE
TODAY...MAINLY BETWEEN 22Z-01Z. WITH A DRIER AIRMASS...CEILINGS
WILL LIKELY STAY ABOVE ILS. SKIES WILL CLEAR TONIGHT WITH SOME
WAVE CLOUDS AFTER MIDNIGHT.

&&

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

$$

SHORT TERM...KRIEDERMAN
LONG TERM...BARJENBRUCH
AVIATION...KRIEDERMAN



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