Area Forecast Discussion
Issued by NWS Pueblo, CO

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000
FXUS65 KPUB 252137
AFDPUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PUEBLO CO
337 PM MDT SAT APR 25 2015

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 223 PM MDT SAT APR 25 2015

...STRONG SPRING STORM SYSTEM ON ITS WAY...

CURRENT WATER VAPOR IMAGERY INDICATING INCREASING SOUTHWEST FLOW
ALOFT ACROSS THE STATE AS A BROAD UPPER TROUGH IS DIGGING INTO THE
GREAT BASIN. WATER VAPOR IMAGERY ALSO INDICATING A LEAD SHORT WAVE
TRANSLATING OUT ACROSS NORTHWESTERN COLORADO AND INTO SOUTH CENTRAL
WYOMING AT THIS TIME. AT THE SFC...LEE TROUGHING IS REDEVELOPING
ACROSS THE I-25 CORRIDOR WITH SOME EASTERLY RETURN FLOW ACROSS THE
EASTERN PLAINS STARTING TO BRING BACK SOME LOW LEVEL MOISTURE WITH
DEW PTS IN THE 30S TO LOWER 40S ACROSS NORTHEASTERN COLORADO AND
INTO SOUTHWESTERN KANSAS AND MAINLY TEENS AND 20S ACROSS THE SOUTH
CENTRAL AND SOUTHEAST COLORADO AT THIS TIME.

THE LATEST MODELS REMAIN IN REMARKABLE AGREEMENT IN DIGGING THE
BROAD UPPER TROUGH ACROSS THE GREAT BASIN TONIGHT. A CLOSED UPPER
LOW PROGGED TO DEVELOP ACROSS NORTHEASTERN ARIZONA AND NORTHWESTERN
NEW MEXICO EARLY SUNDAY MORNING...WHICH CONTINUES TO SLOWLY MOVE
EAST SOUTHEAST INTO NORTH CENTRAL NEW MEXICO THROUGH THE DAY SUNDAY.
THE PROJECTED MOVEMENT OF THIS SYSTEM WILL LIKELY BRING PERIODS OF
MODERATE TO HEAVY RAINFALL TO EASTERN COLORADO ALONG WITH PERIODS OF
MODERATE TO HEAVY WET SNOW FOR THE HIGHER TERRAIN OF SOUTH CENTRAL
AND SOUTHEAST COLORADO.

TONIGHT...SHOULD SEE SCATTERED SHOWERS AND THUNDERSTORMS ACROSS THE
AREA THROUGH THE LATE EVENING WITH LEAD SHORT WAVE CONTINUING TO
MOVE NORTH AND EAST ACROSS SOUTHEASTERN WYOMING AND NORTHEASTERN
COLORADO AND MOIST SOUTH TO SOUTHWEST DIFFLUENT FLOW ACROSS THE
STATE AHEAD OF THE GREAT BASIN SYSTEM. COULD STILL SEE A FEW
STRONGER STORMS TONIGHT ACROSS MAINLY PORTIONS OF KIOWA...BENT AND
PROWERS COUNTIES...THOUGH THE BEST CHANCES LOOK TO REMAIN NORTH OF
THE AREA ACROSS THE NORTHEASTERN PLAINS. LEE TROUGHING STRENGTHENS
ACROSS THE I-25 CORRIDOR WITH EASTERLY LOW LEVEL WINDS CONTINUING TO
BRING IN LOW LEVEL MOISTURE ACROSS THE SOUTHEAST PLAINS OWNING TO
STRATUS AND AREAS OF FOG EXPECTED TO DEVELOP INTO THE EARLY MORNING
HOURS...ESPECIALLY ALONG AND NORTH OF THE HIGHWAY 50 CORRIDOR. COULD
ALSO SEE SOME PATCHY DRIZZLE AS WELL...ESPECIALLY WESTERLY AND
NORTHERN PORTIONS OF EL PASO COUNTY. FURTHER WEST...COULD SEE SOME
LOCAL ACCUMULATIONS OF A COUPLE OF INCHES ACROSS THE HIGHER
ELEVATIONS OF THE SOUTHWEST AND CENTRAL MTS...WITH A BRIEF BREAK IN
PRECIPITATION POSSIBLE LATE TONIGHT.

SUNDAY...SFC TO MID LEVEL EAST TO SOUTHEAST FLOW DEVELOPS ACROSS THE
AREA EARLY SUNDAY MORNING WITH EASTERLY FLOW INCREASING THROUGH THE
AFTERNOON AS THE UPPER LOW CONTINUES TO MOVE INTO NORTH CENTRAL NEW
MEXICO. THIS WILL ALLOW FOR WIDESPREAD PRECIPITATION TO DEVELOP
ACROSS CONTDVD THROUGH THE HIGH MT VALLEYS AND INTO THE EASTERN MTS
THROUGH THE LATE MORNING AND AFTERNOON. SNOW LEVELS TO REMAIN FAIRLY
HIGH THROUGH THE MORNING...GENERALLY AOA 10K FEET...WITH SNOW LEVELS
DROPPING TO AROUND 8K FEET OR LOWER WITH DIABATIC COOLING IN
STRONGER STORMS. CURRENTLY HAVE WINTER STORM WATCHES STARTING AT 15Z
SUNDAY ACROSS THE HIGHER ELEVATIONS OF THE CONTDVD AND THE EASTERN
MTS WITH SNOW ACCUMULATIONS OF 2 TO 4 INCHES POSSIBLE THROUGH THE
AFTERNOON...THOUGH BEST ACCUMULATIONS WILL OCCUR LATER SUNDAY NIGHT.

THERE STILL LOOKS TO BE A BRIEF WINDOW OF STRONG TO SEVERE STORM
POTENTIAL SUNDAY MORNING AND EARLY AFTERNOON ACROSS MAINLY EASTERN
PORTIONS OF HUERFANO AND LAS ANIMAS COUNTIES...WITH MOISTURE POOLING
ALONG A BOUNDARY SUPPORTING MODEST INSTABILITY ALONG WITH ABUNDANT
SHEAR. OTHERWISE...INCREASING INSTABILITY ACROSS THE HIGHER TERRAIN
THROUGH THE AFTERNOON WILL LEAD TO AREAS OF MODERATE TO HEAVY
RAINFALL ACROSS THE AREA BURN SCARS...ESPECIALLY THE WALDO CANYON
AND EAST PEAK SCARS...WITH TRAINING STORMS THROUGH THE AFTERNOON AS
EASTERLY UPSLOPE FLOW STRENGTHENS. PEOPLE LIVING NEAR THE BURN
SCARS SHOULD BE MINDFULL OF THE WEATHER ACROSS THE AREA TOMORROW.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 223 PM MDT SAT APR 25 2015

...HIGH IMPACT HEAVY SNOW EVENT SHAPING UP FOR PORTIONS OF THE
SOUTHEAST MOUNTAINS AND SOUTHERN I-25 CORRIDOR...WITH WIDESPREAD
RAIN ACROSS THE PLAINS...

MODELS STILL IN GOOD AGREEMENT ON EVOLUTION OF THE LOW PRESSURE
SYSTEM WHICH IS CURRENTLY DROPPING SOUTHWARD THROUGH NV AND UT.
MODELS DEVELOP A CLOSED LOW JUST SOUTH OF THE 4 CORNERS REGION ON
SUNDAY THEN TRACK THE SYSTEM ACROSS CENTRAL AND NORTHERN NM SUNDAY
NIGHT...THEN SHIFT IT EASTWARD INTO OK/TX AND SOUTHERN KS BY
MONDAY EVENING. THIS TRACK BRINGS A HEALTHY SHOT OF ISENTROPIC
LIFT ALONG WITH DEEP EAST TO NORTHEASTERLY UPSLOPE FLOW TO THE
REGION SUNDAY NIGHT AND MONDAY. HEAVIEST ACCUMULATIONS STILL LOOK
LIKE THEY WILL IMPACT THE SANGRE DE CRISTO AND WET MOUNTAINS WHERE
1-2 FEET OF HEAVY WET SNOW WILL BE POSSIBLE. SOME MODELS ARE
INDICATING UP TO 3 FEET WILL BE POSSIBLE ACROSS THE HIGHER
AREAS...AND GIVEN THE DYNAMICS OF THIS SYSTEM...CAN`T REALLY RULE
THIS POSSIBILITY OUT. REAL CHALLENGE WILL BE HOW QUICKLY
TEMPERATURES COOL AND HOW LOW SNOW LEVELS DROP SUNDAY NIGHT/EARLY
MONDAY. WITH WITH THE LIKLIHOOD FOR INTENSE PRECIPITATION RATES
WITHIN THE DEFORMATION BAND SUNDAY EVENING...DIABATIC COOLING
COULD DRIVE SNOW LEVELS DOWN TO 6000 FEET...THOUGH THINK SNOW
ACCUMULATIONS WILL BE MORE PERSISTENT ABOVE 7000 FEET...AS
TEMPERATURES WARM AGAIN ON MONDAY AND SOME MELTING OCCURS ACROSS
THE LOWER ELEVATIONS. THIS MAY HELP MITIGATE THE IMPACT SOME FOR
THE ELEVATIONS BETWEEN 6-7KFT.

HAVE UPDATED WINTER STORM WATCHES TO INCLUDE THE WET MOUNTAIN
VALLEY...CENTRAL AND WESTERN FREMONT COUNTY...AND THE SOUTHERN
I-25 CORRIDOR OF WALSENBURG AND TRINIDAD FOR SUNDAY NIGHT AND
MONDAY. HAVE ALSO INCLUDED THE LOWER ELEVATIONS OF
TELLER...CHAFFEE COUNTY...AND THE WESTERN MOSQUITO AND EASTERN
SAWATCH RANGE...THOUGH HOW FAR WEST AND NORTH THE HEAVIER SNOW
WILL FALL IS STILL SOMEWHAT IN QUESTION. FOR NOW...FEEL THERE IS
A 50/50 CHANCE THAT THESE AREAS WILL ATTAIN 8 INCHES OR MORE IN 12
HOURS FOR THE MTN LOCATIONS...AND 6 INCHES OR MORE FOR THE VALLEY
AREAS. GIVEN THE POTENTIAL FOR FOR INTENSE SNOWFALL RATES (2
INCHES PER HOUR)...AND QUICKLY DETERIORATING CONDITIONS...HAVE OPTED
TO INCLUDE THEM IN THE WATCH. SOME OF THE NORTHERN AREAS MAY END
UP UPGRADED TO ADVISORIES INSTEAD OF WARNINGS...BUT TOO SOON TO
SAY AT THIS POINT RIGHT NOW WHERE THE DIVIDING LINE BETWEEN THE
WARNINGS AND THE ADVISORIES WILL END UP. SOUTHWEST MOUNTAINS AND
THE EASTERN SAN JUAN MOUNTAINS SHOULD CONTINUE TO SEE SNOW SUNDAY
NIGHT AND EARLY MONDAY...THOUGH PRECIPITATION WILL TAIL OFF THERE
A BIT EARLIER THAN EVERYWHERE ELSE...AND SNOWFALL AMOUNTS OUT THAT
WAY MAY BE MORE IN THE ADVISORY RANGE...BUT HIGHER ELEVATIONS WILL
BE A CLOSE CALL...SO WILL INCLUDE THEM IN THE WATCH AS WELL. ONE
AREA WHICH ISN`T WELL CAPTURED BY THE CURRENT WINTER STORM WATCHES
IS THE SAN LUIS VALLEY. WHILE THE VALLEY CENTER MAY ONLY PICK UP
AN INCH OR TWO DURING THE OVERNIGHT/EARLY MORNING HOURS SUNDAY
NIGHT/MONDAY MORNING BEFORE TEMPERATURES WARM AND MELT IT OFF
AGAIN...THE VALLEY EDGES COULD SEE SOME SHARP GRADIENTS OF HEAVIER
SNOWFALL. THINK THAT CRESTONE COULD BE ONE OF THESE LOCATIONS AS
EASTERLY FLOW EXTENDS UP TO H3...WELL ABOVE THE SANGRE DE CRISTO
MTN BARRIER. AND THESE EAST WINDS MAY ALSO IMPINGE ON THE EAST
FACING SLOPES OF THE LA GARITAS AS WELL. ALTHOUGH LATEST RUNS ARE
NOT HITTING THESE AREAS ALL THAT HARD...PAST EXPERIENCE WITH
WRAPPED UP LOWS LIKE THIS SUGGEST THAT THERE IS A CHANCE THESE
AREAS COULD BE IMPACTED. WOULD NOT BE SURPRISED TO SEE AN ADVISORY
ISSUED FOR THE SAN LUIS VALLEY TO CAPTURE THIS POTENTIAL
IMPACT...BUT FOR NOW...SNOW AMOUNTS DON`T APPEAR HEAVY ENOUGH AND
WIDESPREAD ENOUGH TO JUSTIFY A WATCH. BUT THOSE NEAR THE VALLEY
EDGES SHOULD KEEP ADVISED OF THE LATEST FORECASTS AND BE PREPARED
FOR THE LIKELIHOOD OF RAPIDLY CHANGING CONDITIONS OVER SHORT
DISTANCES. THE SOUTHERN I-25 CORRIDOR OF HUERFANO AND WESTERN LAS
ANIMAS COUNTY WILL BE ANOTHER TIGHT SNOWFALL GRADIENT ZONE. THINK
THAT WARNING CRITERIA SNOWFALL AMOUNTS WILL BE POSSIBLE WEST OF
I-25...WITH ADVISORY CRITERIA VALUES TO THE EAST. AGAIN...GIVEN
THE SNOWFALL RATES HAVE OPTED TO INCLUDE THESE ZONES IN THE WATCH.
AND FINALLY...NORTHERN EL PASO COUNTY MAY END UP NEEDING AN
ADVISORY AT SOME POINT...BUT TOO MUCH UNCERTAINTY UP THAT WAY FOR
NOW. IN FACT...LOWER ELEVATIONS OF TELLER COUNTY MAY END UP ON
EITHER THE HIGH END ADVISORY OR LOW END WARNING SIDE OF
THINGS...AND ALL WILL DEPEND ON THAT NORTHERN EXTENT OF THE
DEFORMATION BAND. BUT GIVEN THE POTENTIAL FOR INTENSE SNOWFALL
RATES...HAVE INCLUDED THEM WITH THE THOUGHT THAT 8 INCHES WITHIN
12 HOURS MAY BE DOABLE SUNDAY NIGHT.

MEANWHILE...SOUTHEAST PLAINS WILL SEE A WIDESPREAD SOAKING RAIN.
TOTAL QPF AMOUNTS OF 1 TO CLOSE TO 2 INCHES WILL BE
POSSIBLE...WITH THE HEAVIEST AMOUNTS FALLING NEAR THE MOUNTAINS
AND SOUTH OF HIGHWAY 50. GIVEN THE VERY DRY CONDITIONS IN THESE
AREAS...THIS WILL LIKELY BE WELCOME RAINFALL TO MOST. DON`T THINK
RATES WILL BE INTENSE ENOUGH TO CAUSE FLASH FLOODING...BUT WILL
NEED TO WATCH LOW WATER CROSSINGS AND THE LIKE AS THESE WILL
LIKELY SEE SOME ENHANCED FLOWS.

THERE WILL BE A WINDOW SUNDAY EVENING WHERE WE MAY BE WATCHING
THE BURN SCARS CLOSELY UNTIL THE SNOW LEVELS DROP SUFFICIENTLY.
MOST VULNERABLE MAY BE THE EAST PEAK BURN SCAR WHERE INSTABILITIES
MAY BE A LITTLE HIGHER THURSDAY EVENING. BUT WALDO WILL ALSO NEED
TO BE MONITORED CLOSELY. GIVEN THE PATTERN...ITS MORE LIKELY THAT
RATES WILL BE JUST UNDER FLASH FLOOD CRITERIA...BUT WOULD NOT BE
SURPRISED TO SEE THE DRAINAGES RUN WITH WATER...ESPECIALLY SUNDAY
EVENING BEFORE THE RAIN SWITCHES OVER TO SNOW.

AS THE SYSTEM PULLS AWAY TO THE SOUTH AND EAST...SHOULD SEE RAIN
AND SNOW TAPER OFF FROM WEST TO EAST ON MONDAY. GFS HANGS ON TO
PRECIPITATION THE LONGEST...BUT LOOKS TO BE THE OUTLIER WITH A
SLIGHTLY MORE NORTHERN TRACK. IT IS NOT FAVORED BY WPC...THEREFORE
HAVE TRENDED GRIDS CLOSER TO THE 12Z NAM AND ECMWF.

A DRY SPELL RETURNS WITH TEMPERATURES WARMING BACK INTO THE 70S
AND 80S ACROSS THE SOUTHEAST PLAINS BY MID-LATE WEEK AS FLOW
ALOFT BECOMES MORE SOUTHWESTERLY IN ADVANCE OF THE NEXT TROF
MOVING INTO THE WESTERN U.S.  AT LEAST SOME ISOLATED SHOWERS AND
THUNDERSTORMS WILL BE POSSIBLE EACH DAY OVER THE MOUNTAIN
AREAS...BUT PRECIPITATION LOOKS RATHER SPOTTY AT THIS POINT. THE
NEXT CHANCE FOR MORE WIDESPREAD PRECIPITATION MAY COME NEXT
WEEKEND....BUT BOTH GFS AND ECMWF SHOW THIS SYSTEM PASSING WELL
OFF TO THE NORTH...SO PRECIPITATION DOESN`T LOOK ALL THAT
WIDESPREAD OR HEAVY AT THIS POINT. -KT


&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING)
ISSUED AT 223 PM MDT SAT APR 25 2015

VFR CONDITIONS EXPECTED AT COS...PUB AND ALS THROUGH AT LEAST 06Z
SUNDAY...WITH ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS
EXPECTED ACROSS THE HIGHER TERRAIN. BEST CHANCES OF THUNDERSTORMS
AFFECTING ANY OF THE TERMINALS WILL BE AT COS LATE THIS AFTERNOON
AND EVENING...WITH GUSTY OUTFLOW WINDS POSSIBLE.

A STORM SYSTEM MOVING INTO THE FOUR CORNERS REGION THROUGH EARLY
SUNDAY MORNING WILL INCREASE LOW LEVEL MOISTURE ACROSS THE EASTERN
PLAINS...WITH IFR CIGS AND FOG EXPECTED TO DEVELOP AT COS AND PUB
BETWEEN 12Z-16Z SUNDAY...WITH AREAS OF LIGHT RAIN OR DRIZZLE
POSSIBLE. MVFR AND IFR CONDITIONS EXPECTED TO PERSIST WITH PERIODS
OF MODERATE TO HEAVY RAINFALL DEVELOPING THROUGH THE DAY SUNDAY.

MAINLY VFR CONDITIONS EXPECTED AT ALS THROUGH 18Z SUNDAY...WITH
SHOWERS INCREASING ACROSS THE HIGHER TERRAIN SUNDAY MORNING. MVFR
AND LOCAL IFR CONDITIONS WILL BE POSSIBLE AFT 18Z WITH SHOWERS AND
STORMS SPREADING ACROSS THE VALLEY.

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WATCH FROM SUNDAY EVENING THROUGH MONDAY AFTERNOON
FOR COZ061>063-076>078-081-087-088.

WINTER STORM WATCH FROM SUNDAY MORNING THROUGH MONDAY AFTERNOON
FOR COZ058-060-065-066-068-072>075-079-080-082.

&&

$$

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



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