000
FXUS65 KBOU 151505
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
905 AM MDT WED MAY 15 2013

.UPDATE...OVERALL FORECAST LOOKS GOOD. ONLY ADJUSTMENT INVOLVED
INCREASING THE POPS BY 10 PERCENT OR SO IN THE MOUNTAINS...
FOOTHILLS AND URBAN CORRIDOR LATE THIS AFTN AND ERLY EVENING. HRRR
INDICATES THE BEST COVERAGE WHETHER IT BE SHOWERS OR TSTMS WILL
OCCUR AROUND THIS TIME....ALTHOUGH IT COULD ALWAYS BE SOONER.
BRIEF HEAVY RAIN SHOWERS...SMALL HAIL AND GUSTY WINDS THE MAIN
THREAT WITH NO UPPER LEVEL SUPPORT PRESENT FOR ANY SEVERE STORMS.
FCST CAPES NEAR 1000 J/KG WITH TEMPERATURES AROUND 80 AND
DEWPOINTS IN THE LOW 40S. MAIN CONCERN WILL BE OVER THE BURN
AREAS IF A STRONG CELL SETS UP OVER THE BURN SCAR AND BECOMES
STATIONARY. BEST LOW LEVEL MOISTURE HOWEVER WILL BE FURTHER EAST
SO THE OVERALL THREAT FOR SIGNIFICANT FLOODING WILL BE LOW...SEE
THE HYDROLOGY DISCUSSION BELOW.


&&

.AVIATION...ONLY MINOR ADJUSTMENTS TO THE DENVER AREA TAFS AT THIS
TIME. GENERALLY VFR CONDITIONS...WITH BRIEF MVFR CIG/VSBY
RESTRICTIONS THIS AFTN AND EARLY EVENING FM A PASSING TSTM. WL
CARRY VCTS WITH A TEMPO GROUP FOR RAIN SHOWERS VS TSTMS FOR NOW.
GUSTY OUTFLOW WINDS TO 30 KTS AND SOME SMALL HAIL ALSO POSSIBLE
WITH THE STRONGER STORMS.


&&

.PREV DISCUSSION... /ISSUED 353 AM MDT WED MAY 15 2013/

SHORT TERM...A WK UPPER LEVEL FEATURE OVER SRN NEVADA WILL MOVE
EASTWARD INTO WRN CO BY TONIGHT AND THEN INTO ERN CO BY 12Z THU.
AT THE SFC LOW PRES WILL BE OVER SERN CO AS A WK COOL FNT AFFECTS
NERN CO WITH ESE LOW LVL FLOW ACROSS THE PLAINS. MOISTURE TODAY
WILL BE SOMEWHAT BETTER THAN YESTERDAY WITH AFTN CAPES RANGING FM
500-1000 J/KG WITH THE HIGHEST VALUES OVER NERN CO. THUS SHOULD
SEE A BETTER CHC OF SHOWERS AND TSTMS THIS AFTN IN THE MTNS AND
FOOTHILLS AND ACROSS THE PLAINS BY EVENING. OVERALL WIND FIELDS
ALOFT WILL REMAIN RATHER WK THIS AFTN BUT WILL GRADUALLY INCREASE
THIS EVENING AS THE DISTURBANCE MENTIONED ABV MOVES INTO WRN
COLORADO. OVERALL THREAT OF SVR WX LOOKS LOW THIS AFTN AND EVENING
ALTHOUGH A FEW STORMS OVER THE PLAINS COULD PRODUCE SOME SMALL
HAIL AND SOME HEAVIER RAIN IN A FEW SPOTS DUE TO INITIAL SLOW
MOVEMENT OF STORMS. HIGHS THIS AFTN WILL NOT BE AS WRM AS TUE
HOWEVER READINGS WILL STILL BE AROUND 10 DEGREES ABV NORMAL OVER
NERN CO.

LONG TERM...THURSDAY AND FRIDAY WILL SEE A FEW DEGREES OF WARMING
AND A LOWER CHANCE OF SHOWERS AS DRIER SOUTHWEST FLOW ALOFT MOVES
OVER THE STATE. FROM SATURDAY ONWARD...TEMPERATURES WILL BE
GRADUALLY COOLING WITH AN INCREASE IN SHOWERS AS A BROAD UPPER
TROUGH CARVES OUT OVER THE GREAT BASIN AND CENTRAL ROCKIES THEN
REMAINS OVER THE REGION EARLY NEXT WEEK. THE TROUGH WILL NOT BE
PARTICULARLY STRONG OR COLD...BUT WILL PRODUCE UNSETTLED
CONDITIONS BY PROVIDING UPWARD FORCING TO THE AIRMASS. EARLY ON IN
THE WEEKEND...THE SURFACE PRESSURE PATTERN WILL BE SUCH THAT
MOISTURE FROM THE GULF OF MEXICO WILL BE ABLE TO ADVECT INTO
EASTERN COLORADO. LATER IN THE WEEKEND...THE SURFACE TROUGH OVER
EASTERN COLORADO WILL SHIFT FURTHER EAST...POSSIBLY PULLING THE
MOISTURE WITH IT. HOWEVER...SINCE THE ENTIRE UPPER PATTERN OVER
THE WESTERN U.S. WILL BE SO BLOCKED...WE MAY BE DEALING WITH MID-
LEVEL MOISTURE THROUGH THE LATTER HALF OF THE FORECAST PERIOD.
ISOLATED TO SCATTERED SHOWERS ARE GOING TO BE POSSIBLE EACH DAY...
WITH THE CHANCE OF THUNDER DURING THE AFTERNOONS DUE TO THE
DIURNAL HEATING THAT WILL TAKE PLACE. DYNAMIC FORCING WITH THE
UPPER TROUGH NEVER GETS STRONG...SO THE THREAT OF SEVERE
THUNDERSTORMS LOOKS MINIMAL FOR NOW. BASED ON MOS TEMPERATURE
GUIDANCE...IT APPEARS THAT THE COOLING TREND WILL CONTINUE INTO
MONDAY AND TUESDAY BEFORE TEMPERATURES START WARMING AGAIN.

AVIATION...THERE WILL BE A BETTER CHC OF TSTMS THIS AFTN IN THE
21Z-00Z TIMEFRAME. CEILINGS AND VISIBILTIES COULD BRIEFLY DROP
DOWN TO MVFR IF A STRONGER STORM AFFECTS THE AIRPORT. AFTER 00Z
BEST CHC OF STORMS SHOULD BE EAST OF THE AIRPORT. WINDS WERE
DRAINAGE EARLY THIS MORNING BUT SHOULD BECOME MORE NE BY 16Z AS A
WK FNT MOVES ACROSS. OUTFLOW BOUNDARIES FM AFTN CONVECTION WILL
PLAY HAVOC WITH WINDS AS THEY WILL LIKELY BECOME MORE W OR SW WITH
PASSAGE OF CONVECTION AFTER 22Z WITH SOME BRIEF GUSTS TO 30 MPH.
FOR THIS EVENING WINDS SHOULD TRANSITION BACK TO DRAINAGE AFTER
SUNSET.

HYDROLOGY...RAINFALL AMOUNTS UP TO A QUARTER INCH IN 30 MINUTES
WILL BE POSSIBLE WITH ISOLATED AMOUNTS UP TO ONE HALF INCH IF A
HEAVIER SHOWER WERE TO MOVE OVER ANY OF THE BURN AREAS THIS AFTN.
THE STORM THREAT SHOULD END BY 01Z IN THE BURN AREAS.

&&

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

$$

SHORT TERM...COOPER
LONG TERM....D-L
AVIATION...COOPER