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000
FXUS65 KPUB 182118
AFDPUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PUEBLO CO
318 PM MDT FRI APR 18 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 318 PM MDT FRI APR 18 2014

..WARM SYSTEM BRINGING RAIN AND HIGHER ELEVATION SNOW TO THE REGION
FOR SATURDAY...

UPPER LOW IS CURRENTLY MOVING ONSHORE THROUGH SOUTHERN CA WITH A
GOOD FETCH OF MOISTURE SPREADING ACROSS THE DESERT SOUTHWEST INTO SW
CO AHEAD OF THIS SYSTEM.  FOR LATE THIS AFTERNOON THROUGH THIS
EVENING...LATEST HIGH RES MODELS SEEM TO BE BACKING OFF ON ISOLATED
-SHRA/-TSRA POTENTIAL ACROSS THE MOUNTAINS...AND HAVE DECREASED POPS
A BIT ACCORDINGLY.

LEADING VORT MAX WILL BE EJECTING INTO THE 4 CORNERS REGION LATER
TONIGHT...THEN ACROSS CENTRAL AND EASTERN PORTIONS OF THE FORECAST
AREA SATURDAY MORNING.  THIS IS WHEN THE BRUNT OF THE RAIN/SNOW WILL
SPREAD INTO THE SOUTHWEST AND CENTRAL MOUNTAINS...WITH THE POTENTIAL
FOR SOME ISOLATED SHOWERS MAINTAINING AS THEY LIFT TO THE NORTHEAST
ACROSS THE SOUTHEAST MOUNTAINS/ADJACENT PLAINS DURING THE MORNING.
GIVEN ITS PACIFIC ORIGIN...WET BULB ZEROS ARE RATHER HIGH...WITH
RAIN/SNOW LINE RANGING FROM 9500-10000 FEET TONIGHT...AND AROUND 10-
10.5 KFT ON SATURDAY. PRECIPITABLE WATERS WITH THIS SYSTEM ARE
FORECAST TO BE WELL ABOVE NORMAL...BY AS MUCH AS 2 STANDARD
DEVIATIONS FOR THIS TIME OF YEAR GIVEN FORECAST VALUES OF .55 TO .62
ACCORDING TO NAM/GFS. THIS RAISES CONCERNS FOR POTENTIAL FOR HEAVY
RAIN ON THE AREA BURN SCARS WHICH HAVE LOW RAIN RATE THRESHOLDS FOR
FLASH FLOODING. THE BURN SCAR WITH THE GREATEST CONCERN WILL BE
WALDO GIVEN ITS VERY LOW THRESHOLDS (GT OR EQ TO .50 PER HOUR FOR
FLASH FLOODING).

THE DEVIL IS ALWAYS IN THE DETAILS THOUGH.  FIRST...MODEL SOUNDINGS
SUGGEST QUITE A BIT OF PERSISTENT MID/HIGH CLOUDINESS ON
SATURDAY...WHICH WOULD LIMIT POTENTIAL INSTABILITY.  THIS WOULD
RESULT IN WEAKER UPDRAFT STRENGTHS AND RESULT IN RAINFALL RATES
REMAINING BELOW THE FLASH FLOOD WARNING CRITERIA. HOWEVER THERE IS A
FRONT WHICH DROPS IN AND ATTEMPTS TO FOCUS CONVECTION ACROSS THE
PIKES PEAK REGION IN THE AFTERNOON.  IF WE CAN GET SOME SUN BREAKS
AND ENOUGH MOISTURE RETURN BEHIND THE FRONT TO REALIZE SOME
INSTABILITY...THEN WE COULD SEE SOME ISOLATED STRONGER STORMS THAT
COULD RESULT IN LOCALIZED FLASH FLOODING...IF THE BURN SCAR IS
UNLUCKY ENOUGH TO TAKE A DIRECT HIT.  FOR NOW...THINK THE MOST
LIKELY SCENARIO WILL BE FOR A COUPLE ROUNDS OF LIGHT TO MODERATE
RAIN...WITH RAINFALL RATES REMAINING BELOW .20...AND AT
TIMES...BETWEEN .20 AND .40 PER HOUR.  THEREFORE NO FLASH FLOOD
WATCHES LOOK NEEDED AT THIS POINT.  HOWEVER GIVEN THE TRANSITION
TOWARDS SPRING AND THE RESULTANT HIGHER SNOW LEVELS WITH THIS WARMER
SYSTEM...THOSE IN AND NEAR THE WALDO BURN SCAR SHOULD REMAIN ALERT
TO THE CHANGING WEATHER CONDITIONS ON SATURDAY...AND BE PREPARED TO
TAKE ACTION IF NECESSARY.

SHOWERS AND THUNDERSTORMS WILL SPREAD ACROSS THE PLAINS DURING THE
AFTERNOON AS THE FRONT ROLLS THROUGH.  LIMITED DEW POINT RETURN
RESULTS IN CAPE VALUES AROUND OR BELOW 500 J/KG...SO NO SEVERE
THUNDERSTORMS ARE ANTICIPATED.  HIGHER ELEVATION THUNDERSTORMS COULD
PRODUCE SOME SMALL HAIL WITH ANY OF THE STRONGER UPDRAFTS DUE TO THE
RELATIVELY LOW FREEZING LEVELS...AND OF COURSE...LIGHTNING IS A
CONCERN WITH ANY THUNDERSTORMS.

ABOVE 10-11KFT...SNOWFALL AMOUNTS OF 1 TO 4 INCHES WILL BE POSSIBLE
THROUGH SATURDAY...THOUGH THIS WILL BE CONFINED TO THE HIGHER
ELEVATIONS AND NO HIGHLIGHTS SHOULD BE NEEDED. -KT

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 318 PM MDT FRI APR 18 2014

SATURDAY NIGHT-SUNDAY NIGHT...SOME DIFFERENCES IN MODEL HANDLING OF
BROAD UPPER TROUGH AND WEAKENING UPPER LOW TRANSLATING ACROSS THE
ROCKIES AND HAVE STAYED CLOSER TO THE NAM AND ECMWF SOLUTIONS WHICH
ARE A TAD FURTHER SOUTH WITH MAIN PIECE OF THE SYSTEM THAN THE GFS.
AT ANY RATE...WITH AMPLE MID AND UPPER LEVEL MOISTURE AND SOME UVV
AHEAD OF BROAD TROUGH...SHOULD SEE SCATTERED SHOWERS AND
THUNDERSTORMS ACROSS THE AREA THROUGH SATURDAY EVENING...WITH BEST
POPS ACROSS THE EASTERN MTS AND PLAINS ASSOCIATED WITH WEAK FRONTAL
BOUNDARY MOVING THROUGH EASTERN COLORADO. SHOWERS LOOK TO BE ON THE
WANE LATE SATURDAY NIGHT AND EARLY SUNDAY...WITH SCATTERED SHOWERS
AND STORMS DEVELOPING ONCE AGAIN LATE SUNDAY MORNING AND AFTERNOON
AS BROAD UPPER TROUGH CONTINUES TO LIFT OUT ACROSS THE STATE.

MODELS CONTINUE TO INDICATE PWATS BETWEEN 0.50 AND 0.75 INCHES
THROUGH THE DAY SUNDAY...WHICH IS 2 TO 3 TIMES NORMAL FOR THIS TIME
OF YEAR. THIS WOULD SUPPORT THE POTENTIAL FOR LOCALLY HEAVY RAINFALL
AND FLASH FLOODING...MAINLY ACROSS AREA BURN SCARS. HOWEVER...WITH
LIMITED INSTABLITY AND THE MAIN PORTION OF THE SYSTEM LIKELY STAYING
TO THE SOUTH...THE FLASH FLOODING THREAT LOOKS TO BE FAIRLY LOW AT
THIS TIME.

MONDAY-WEDENSDAY...SHORT WAVE RIDGING ACROSS THE AREA MONDAY WILL
GIVE WAY TO INCREASING WEST TO SOUTHWEST FLOW ALOFT ACROSS THE
REGION AS EASTERN PACIFIC ENERGY MOVING ONSHORE ACROSS THE PAC NW
CONTINUES ACROSS THE GREAT BASIN AND INTO THE NORTHERN ROCKIES
WEDNESDAY. WEAK UPSLOPE ACROSS THE PLAINS AND SOME RESIDUAL MOISTURE
ACROSS THE AREA ON MONDAY WILL MAY DEVELOP ISOLATED SHOWERS ACROSS
THE HIGHER TERRAIN AND ADJACENT PLAINS IN THE AFTERNOON AND EARLY
EVENING. INCREASING FLOW ALOFT WILL DEVELOP LEE TROUGHING ACROSS THE
PLAINS TUESDAY WITH INCREASING FIRE DANGER...ESPECIALLY ALONG AND
THE I-25 CORRIDOR THROUGH THE AFTERNOON. COULD SEE SOME SHOWERS
ACROSS THE HIGHER TERRAIN AS WELL AS THE FAR SE PLAINS...THOUGH
DRYLINE LOOKS TO BE EAST OF THE AREA INTO WESTERN KANSAS. FIRE
DANGER CONTINUES TO INCREASE ACROSS ALL OF THE LOWER ELEVATIONS ON
WEDNESDAY WITH WARM...DRY AND WINDY WEATHER EXPECTED AS JET STREAM
ASSOCIATED WITH NORTHERN ROCKIES SYSTEM TRANSLATES ACROSS THE STATE.

THURSDAY-FRIDAY...SLIGHTLY COOLER AND CONTINUED WINDY WEATHER FOR
THURSDAY WITH MODERATE WEST TO NORTHWEST FLOW ALOFT BEHIND PASSING
SYSTEM. SHORT WAVE RIDGING PROGGED ACROSS THE STATE ON FRIDAY WITH
DRY WEATHER AND SEASONAL TEMPERATURES ON TAP.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 318 PM MDT FRI APR 18 2014

VFR CONDITIONS EXPECTED TONIGHT...THOUGH MID AND HIGH
CLOUDINESS WILL BE SPREADING IN AND THICKENING TOWARDS MORNING.
SCATTERED RAIN AND SNOW SHOWERS WILL IMPACT THE SOUTHWEST AND
CENTRAL MOUNTAINS...PARTICULARLY AFTER 06Z...WITH A BAND OF SHOWERS
POSSIBLY MAINTAINING AS IT LIFTS TO THE NORTHEAST TO THE VCNTY OF
KCOS AND KPUB DURING THE MORNING.  LESS CERTAINTY EXISTS AS TO HOW
PERSISTENT THIS BAND WILL BE...THUS HAVE VCSH FOR KCOS ONLY IN THE
MORNING.  A COLD WILL DROP SOUTH OF THE PALMER DIVIDE BY 15Z...WITH
NORTH WINDS SPREADING INTO KCOS AND KPUB DURING THE MORNING.  SPEEDS
WILL BE AROUND 10-15 KTS.  SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE AT ALL THREE TAF SITES DURING THE AFTERNOON...BUT WILL BE
MOST LIKELY TO OCCUR AT KCOS.  PRECIPITATION WILL FALL AS RAIN AT
ALL THREE TAF SITES WITH SNOW LEVELS REMAINING CONFINED TO ABOVE
10KFT.  CIGS WILL LIKELY REMAIN VFR...BUT COULD BRIEFLY DROP INTO
THE MVFR CATEGORY WITH HEAVIER SHOWERS SATURDAY AFTERNOON. -KT

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...KT
LONG TERM...MW
AVIATION...KT