694
FXUS65 KPUB 201145
AFDPUB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PUEBLO CO
445 AM MST WED FEB 20 2019
SHORT TERM
(TODAY AND TONIGHT)
ISSUED AT 438 AM MST WED FEB 20 2019
SNOW HAS COME TO AN END ACROSS THE AREA EARLY THIS MORNING AS UPPER
TROUGH PULLS AWAY INTO THE CENTRAL PLAINS, WITH JUST SOME LINGERING
CLOUDS OVER THE CONTINENTAL DIVIDE AND THE CREST OF THE SANGRES, AND
A COUPLE PATCHES OF STRATUS AND FOG ON THE PLAINS. FOR TODAY, BRIEF
SHORT WAVE RIDGE DRIFTS ACROSS CO EARLY, BEFORE FLOW BEGINS TO BEND
BACK TO THE SOUTHWEST BY LATE AFTERNOON AS NEXT UPPER SYSTEM DIGS
INTO THE GREAT BASIN. FIRST HALF OF THE DAY SHOULD BE MAINLY DRY
ACROSS THE REGION, WITH ONLY A FEW LIGHT FLURRIES OVER THE HIGHER
PEAKS ALONG THE DIVIDE THROUGH MIDDAY. SNOW SHOWERS THEN GRADUALLY
INCREASE IN COVERAGE OVER THE SAN JUANS AND LA GARITAS DURING THE
AFTERNOON AS MID LEVEL MOISTURE DEEPENS, THOUGH ANY ACCUMS THROUGH
SUNSET SHOULD BE RATHER LIGHT. WITH A DECREASE IN CLOUDS AND AT
LEAST A WEAK WLY COMPONENT TO THE LOW LEVEL WIND FIELD, MOST AREAS
SHOULD SEE MAX TEMPS WARM SEVERAL DEGF FROM THE PAST FEW DAYS,
THOUGH READINGS AREA-WIDE WILL STILL BE WELL BELOW SEASONAL
AVERAGES. TONIGHT, GREAT BASIN TROUGH CONTINUES TO DEEPEN, WITH
STRENGTHENING MOIST SW FLOW ALONG THE CONTINENTAL DIVIDE. WINTER
STORM WARNING LOOKS GOOD, AS SNOW SHOULD BECOME HEAVY ACROSS THE SAN
JUANS/LA GARITAS OVERNIGHT, WITH SEVERAL INCHES OF ACCUMULATION BY
EARLY THU MORNING. FARTHER NORTH ALONG THE DIVIDE, SNOW WILL
DEVELOP, THOUGH ACCUMS WILL BE MUCH LIGHTER AS SW FLOW IS LESS
FAVORABLE FOR HEAVY SNOW HERE. JUST INCREASING CLOUDS FARTHER EAST,
WHICH WILL KEEP MIN TEMPS SLIGHTLY WARMER MANY AREAS VERSUS THE PAST
FEW DAYS.
LONG TERM
(THURSDAY THROUGH TUESDAY)
ISSUED AT 438 AM MST WED FEB 20 2019
THURSDAY - FRIDAY...
THE AFOREMENTIONED UPPER LEVEL TROUGH CONTINUES TO SLOWLY DIG
SOUTH THROUGH THE SOUTHWEST US THURSDAY AND FRIDAY. AN ASSOCIATED
SOUTHWESTERLY 110+ KNOT 300 MB JET WILL REMAIN ORIENTED ACROSS THE
MIDDLE OF THE STATE. FINALLY, THE UPPER TROUGH WILL BE POSITIONED
TO DRIVE PACIFIC MOISTURE NORTHEAST INTO COLORADO. DETERMINISTIC
AND ENSEMBLE MODEL GUIDANCE HAS BEEN CONSISTENT IN THE EARLY
EVOLUTION OF THIS STORM SYSTEM, LEADING TO HIGH CONFIDENCE IN THE
FORECAST DURING THIS PERIOD.
THE SLOW MOVEMENT OF THE STORM SYSTEM WILL LEAD TO A PROLONGED
PERIOD OF SNOWFALL ACROSS THE HIGH TERRAIN. THE MORE WIDESPREAD
AND HEAVIER SNOW WILL BE CONFINED TO THE EASTERN SAN JUANS AND LA
GARITAS DURING THE DAY THURSDAY WHERE QG FORCING FOR ASCENT AND
OROGRAPHIC FLOW WILL BE MOST FAVORABLE. CONSIDERING STRONG
SOUTHWEST FLOW INTO SOUTHWEST/SOUTH-CENTRAL COLORADO, THE EASTERN
SAN JUANS ARE WELL POSITIONED TO RECEIVE THE MOST SNOWFALL FROM
THIS SYSTEM. THE FORECAST STILL HAS ABOUT 1-3 FEET OF SNOWFALL,
WITH THE WINTER STORM WARNING STILL LOOKING THROUGH 00Z FRIDAY
EVENING. THE LA GARITAS, ALSO IN THE WINTER STORM WARNING, ARE
EXPECTED TO SEE 12-18 INCHES OF SNOWFALL. SNOW WILL PICK UP OVER
THE CENTRAL AND EASTERN MOUNTAINS THURSDAY NIGHT INTO FRIDAY AS
THE SYSTEM SHIFTS EAST AND QG FORCING INCREASES OVER THOSE AREAS.
IT CURRENTLY LOOKS LIKE THESE AREAS WILL RECEIVE HIGH END ADVISORY
SNOW TOTALS, SO WILL HOLD OFF ON ISSUING HIGHLIGHTS. LOCATIONS IN
THE SAN LUIS VALLEY AND UPPER ARKANSAS RIVER VALLEY SHOULD SEE
1-4 INCHES OF SNOWFALL.
THE PLAINS WILL REMAIN DRY THURSDAY AND FRIDAY AS THE UPPER
TROUGH AND ASSOCIATED FORCING REMAINS WELL TO THE WEST, AND DRYING
DOWNSLOPE FLOW SPREADS ACROSS THE PLAINS. THERE IS A CHANCE THAT
AN ISOLATED SNOW SHOWER MOVES EAST OFF THE HIGH TERRAIN, BUT WOULD
LIKELY STAY WEST OF I-25. DEEP VERTICAL MIXING EACH AFTERNOON AND
STRONG FLOW ALOFT WILL LEAD TO BREEZY CONDITIONS ACROSS THE
PLAINS EACH AFTERNOON AND EARLY EVENING, MAINLY ALONG THE SOUTHERN
AND EASTERN PORTIONS OF THE PLAINS. TEMPERATURES WILL CONTINUE TO
WARM, WITH HIGHS IN THE MID/UPPER 40S ON THURSDAY AND UPPER 40S
TO LOW 50S ON FRIDAY.
FRIDAY NIGHT - SATURDAY...
THE UPPER TROUGH ACCELERATES EAST AND INTENSIFIES/CLOSES
SOMEWHERE NEAR THE SOUTHEAST COLORADO AND NORTHEAST NEW MEXICO
BORDER. ALTHOUGH THE LAST FEW ROUNDS OF MODEL CYCLES HAVE MOVED
THE LOW EAST QUICKER THAN PREVIOUSLY, MODELS ARE COMING INTO
AGREEMENT ON THE EXACT POSITION OF THE LOW AS IT ADVANCES EAST. BY
12Z SATURDAY, THE ECMWF, GFS, FV3, CMC, AND NAM ALL HAVE THE
UPPER LOW CENTERED OVER THE NORTHEAST NEW MEXICO AND OK/TX
PANHANDLE REGION, SOUTH OF THE COLORADO BORDER, IN A FAVORABLE
POSITION FOR PRECIP OVER SOUTHEAST COLORADO. ENSEMBLE SPREAD IS
ALSO QUITE LOW, WITH MAIN DIFFERENCES LYING IN THE SPEED OF THE
TROUGH AS IT EXITS ONTO THE PLAINS. GIVEN MODEL MODEL AGREEMENT ON
THE POSITION OF THE LOW, BUT STILL TIMING FLUCTUATIONS AND TIME
UNTIL EVENT, CONFIDENCE IN THIS PART OF THE FORECAST HAS INCREASED
TO MODERATE.
AS THE LOW SHIFTS EAST AND INTENSIFIES, QG FORCING AND
ATMOSPHERIC MOISTURE WILL INCREASE OVER THE PLAINS, WITH TPW
REACHING CLOSE TO 0.5". THE SYSTEM WILL ALSO DRIVE A COLD FRONT
DOWN THE EASTERN COLORADO PLAINS DURING THE EVENING AS A SURFACE
LOW DEEPENS AND EXITS EAST OUT OF SOUTHEAST COLORADO. RAIN AND
SNOW SHOWERS WILL INCREASE ACROSS ALL OF THE PLAINS LATE FRIDAY
AFTERNOON AND CONTINUE THROUGH THE EVENING. PRECIP WILL QUICKLY
CHANGE TO ALL SNOW AND BECOME HEAVIEST EARLY SATURDAY MORNING
BEHIND THE COLD FRONT ON THE WRAP AROUND PORTION OF THE SYSTEM AS
ISENTROPIC SURFACES RAPIDLY RISE. GIVEN THE RELATIVELY QUICK
MOVEMENT OF THE SYSTEM EAST, PRECIP CHANCES/AMOUNTS LOOK BEST OVER
FAR EASTERN COLORADO NEAR THE KANSAS BORDER, BECOMING ISOLATED TO
SCATTERED WITH ONLY LIGHT AMOUNTS OVER THE I-25 CORRIDOR. MODELS
CONTINUE TO PRODUCE QPF UP TO 0.5" OVER THE FAR EASTERN PLAINS.
SNOW ACCUMULATIONS OF AT LEAST A FEW INCHES SEEM PROBABLE ACROSS
A PORTION OF THE EASTERN PLAINS EAST OF THE I-25 CORRIDOR, BUT
SHOULD STAY RELATIVELY LIMITED CONSIDERING THE FAST EXIT OF THE
LOW.
PRECIP WILL LIKELY BE OVER ACROSS THE FORECAST AREA BY EARLY
SATURDAY AFTERNOON. TEMPERATURES SATURDAY WILL ONLY BE SLIGHTLY
COOLER, WITH HIGHS IN THE LOW TO MID 40S EXPECTED ACROSS THE
PLAINS. BREEZY NORTH TO NORTHWEST WINDS DURING THE FIRST HALF OF
THE DAY WILL BECOME LIGHT BY EVENING.
SATURDAY NIGHT - TUESDAY...
BEHIND THE TROUGH, UPPER LEVEL FLOW WILL BECOME WESTERLY AND
RELATIVELY UNDISTURBED, LEADING TO MAINLY DRY CONDITIONS ACROSS
THE FORECAST AREA. SUBTLE DISTURBANCES MAY BRING BRIEF PERIODS OF
LIGHT SNOW SHOWERS TO THE CONTINENTAL DIVIDE, PARTICULARLY OVER
THE CENTRAL MOUNTAINS. HIGH TEMPERATURES WILL GENERALLY SPAN THE
40S ACROSS THE PLAINS, AND 30S IN THE HIGH VALLEYS.
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 438 AM MST WED FEB 20 2019
AT KALS, VFR TODAY AND TONIGHT, WITH SLOWLY LOWERING VFR CIGS AFTER
00Z. MAY SEE AN ISOLATED -SHSN TOWARD EARLY THU MORNING AS PRECIP
SPILLS EAST FROM THE CONTINENTAL DIVIDE, THOUGH CHANCE LOOKS TOO LOW
TO INCLUDE IN THE 12Z TAF. AT KCOS, VFR TODAY AND TONIGHT, THOUGH
WILL NEED TO WATCH AREA OF STRATUS AND FOG JUST SOUTHEAST OF THE
TERMINAL EARLY THIS MORNING, AS WEAK SE WIND DEVELOPING AFTER
SUNRISE MAY PUSH CLOUDS CLOSE TO THE AIRPORT 12Z-15Z. AT KPUB, WRN
EDGE OF LOW CLOUDS AND FOG NEAR THE TERMINAL EARLY THIS MORNING,
THOUGH SATELLITE TRENDS AND WEAK LOW LEVEL WLY WIND SUGGEST WORST
VIS AND LOWEST CIGS MAY STAY JUST EAST OF THE AIRPORT. MAY SEE AN HR
OR TWO OF MVFR OR IFR CONDITIONS IN THE 12Z-15Z PERIOD, THOUGH WILL
WAIT UNTIL ISSUANCE TIME TO DECIDE ON EXTENT OF LOW CLOUDS. ONCE
CLOUDS CLEAR BY MID-MORNING, VFR CONDITIONS EXPECTED FOR THE
REMAINDER OF THE DAY AND TONIGHT.
PUB WATCHES/WARNINGS/ADVISORIES
WINTER STORM WARNING FROM 5 PM THIS AFTERNOON TO 5 PM MST FRIDAY
FOR COZ066-068.
SHORT TERM...PETERSEN
LONG TERM...LINE
AVIATION...PETERSEN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page