Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 042054
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
254 PM MDT MON MAY 4 2015

.SHORT TERM...(THIS EVENING THROUGH TUESDAY)
ISSUED AT 129 PM MDT MON MAY 4 2015

LIGHTNING HAS BEEN ON THE INCREASE ACROSS THE STATE THIS EARLY
AFTERNOON...WITH A FEW STORMS ALONG THE PALMER DIVIDE. STORM
MOTION HAS BEEN TOWARDS THE NORTH NORTHEAST...AND RAINFALL RATES
THUS FAR OVER THE DIVIDE HAVE BEEN MOSTLY LESS THAN AN INCH AN
HOUR. GIVEN THAT...PRECIPITABLE WATER VALUES ARE IN NEAR RECORD
TERRITORY FOR EARLY MAY...WITH NAM FORECASTING 0.88 INCHES THIS
EVENING. SO WILL HAVE TO WATCH FOR POSSIBLE HEAVY RAIN WITH
STORMS...BUT OVERALL THREAT OF SIGNIFICANT FLOODING IS LOW.
INITIALLY OVER THE ELEVATED TERRAIN THERE MAY BE SOME SMALL HAIL
WITH THESE STORMS. EXPECT CONVECTION TO CONTINUE TO INCREASE THIS
EVENING...THEN A TRANSITION TO MOSTLY RAIN SHOWERS LATER THIS
EVENING...MIXING WITH STATUS AND FOG OVERNIGHT.

LIGHT PRECIPITATION IS EXPECTED TUESDAY EARLY...THEN ANOTHER
ROUND WIDESPREAD SHOWERS AND THUNDERSTORMS IN THE AFTERNOON...
PROBABLY MORE WIDESPREAD AS THE UPPER LOW APPROACHES FROM THE
SOUTHWEST. AGAIN THE MAIN THREAT TUESDAY WILL BE LOCALLY HEAVY
RAIN WITH THE STORMS...BUT CANNOT RULE OUT SMALL HAIL AS LIFT
ASSOCIATED WITH THE UPPER LOW APPROACHES.

.LONG TERM...(TUESDAY NIGHT THROUGH MONDAY)
ISSUED AT 129 PM MDT MON MAY 4 2015

A DAMP AND COOL PERIOD WILL PREVAIL THROUGH MUCH OF THE LONG TERM.
THE MODELS ARE ALL PRETTY CONSISTENT LIFTING THE LOW OVER COLORADO
TUESDAY NIGHT AND WEDNESDAY WITH ATTENDANT QUASIGEOSTROPHIC ASCENT
KEEPING THE PRECIPITATION THREAT HIGH. THERE IS A BIT OF LARGE
SCALE SUBSIDENCE FORECAST TO MOVE OVERHEAD WEDNESDAY EVENING AND
EARLY THURSDAY WHICH WILL PROBABLY RESULT IN LOWER BUT NOT
NECESSARILY ZERO POPS DURING THAT TIME FRAME. INCREASING UPSLOPE
FLOW AND QG ASCENT ASSOCIATED WITH ANOTHER UPPER LEVEL LOW WILL
RETURN LATER THURSDAY AND CONTINUE THROUGH AT LEAST LATE SATURDAY
AND PERHAPS INTO SUNDAY. THIS WILL RAMP UP THE PRECIPITATION
THREAT AGAIN FOR LATER IN THE WEEK...PERHAPS LEADING TO A
SUBSTANTIAL RAIN/SNOW EVENT BY THE WEEKEND...DEPENDING AS
USUAL...ON THE EXACT TRACK OF THE CYCLONE. SUBSIDENCE...DRYING AND
WARMING LOOK TO BE IN STORE FOR EARLY NEXT WEEK AS THIS SECOND
FEATURE MOVES INTO THE GREAT PLAINS.

ALL IN ALL IT LOOKS LIKE THE SEVERE WEATHER THREAT SHOULD REMAIN
RATHER LOW THROUGH MOST OF THIS TIME FRAME BASED ON FORECAST CAPE
VALUES ALTHOUGH THE THREAT OF THUNDERSTORMS WILL BE AROUND...
ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS. FORECAST
PRECIPITABLE WATER VALUES ARE HIGH ENOUGH TO ALLOW FOR SOME DECENT
QPF...ESPECIALLY IN HEAVIER SHOWERS AND THUNDERSTORMS. BURN SCARS
IN THE FOOTHILLS COULD HAVE SOME ISSUES IF A STRONGER CONVECTIVE
CELL WERE TO PASS BY.

&&

.AVIATION...(FOR THE TAFS THROUGH 00Z TUESDAY LATE AFTERNOON)
ISSUED AT 129 PM MDT MON MAY 4 2015

IT WILL BE A WEATHERY PERIOD WITH SHOWERS AND THUNDERSTORMS
BECOMING LIKELY LATE THIS AFTERNOON AND EVENING...THEN SHOWERS
LIKELY OVERNIGHT. STRATUS THIS AFTERNOON WILL BE MAINLY VFR...BUT
WITH PRECIPITATION EXPECT MVFR CONDITIONS. LATER THIS EVENING AND
OVERNIGHT CEILINGS AND VISIBILITIES WILL BE MAINLY MVFR WITH SOME
SPOTTY IFR CONDITIONS. THERE SHOULD BE A FEW HOURS OF IMPROVEMENT
THROUGH MIDDAY TUESDAY...THEN IN THE AFTERNOON THERE WILL BE
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS PRODUCING MVFR
CONDITIONS.

&&

.HYDROLOGY...
ISSUED AT 129 PM MDT MON MAY 4 2015

THE OVERALL THREAT OF FLOODING IN BURN AREAS WILL BE LOW...AS
STORMS CONTINUE TO TRACK TOWARDS THE NORTHEAST. PRECIPITABLE
WATER VALUES ARE HIGH FOR EARLY MAY SO INDIVIDUAL STORMS MY
PRODUCE A QUICK INCH OF RAIN...BUT THE STORMS WILL CONTINUE TO
MOVE AROUND 10MPH. AS THUNDERSTORMS BECOME MAINLY STRATIFORM
PRECIPITATION LATER THIS EVENING PRECIPITATION RATES WILL
DECREASE. WILL HAVE TO WATCH AGAIN ON TUESDAY AS SHOWERS AND
THUNDERSTORMS BECOME WIDESPREAD IN THE AFTERNOON...WITH THE LIFT
ASSOCIATED WITH THE UPPER LOW MOVING CLOSER AND HIGH PRECIPITABLE
WATER VALUES THROUGH THE EVENING.

&&

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

&&

$$

SHORT TERM...RTG
LONG TERM...ET
AVIATION...RTG
HYDROLOGY...RTG


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