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000
FXUS65 KBOU 021147 CCA
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
420 AM MST SUN MAR 2 2014

...CORRECTION TO LAST PARAGRAPH OF LONG TERM DISCUSSION

.SHORT TERM...TODAY AND TONIGHT...THE STRONG PACIFIC CLOSED LOW HAS
WEAKENED AND FILLED AS IT MOVED INLAND AND IS NOW AN OPEN TROUGH
MOVING ACROSS ARIZONA. STILL GOOD ASCENT AHEAD OF THE TROUGH AND IS
PRODUCING PRECIPITATION ACROSS EASTERN ARIZONA AND INTO SOUTHWEST
COLORADO. EXPECT AN AREA OF SNOW TO MOVE ACROSS SOUTHERN COLORADO
TODAY. THE SNOW MAY CLIP LINCOLN COUNTY AND WILL INCREASE POPS FOR
THIS. SNOW SHOWERS WILL REMAIN POSSIBLE IN THE MOUNTAINS
TODAY...WITH JUST A SLIGHT CHANCE FOR SNOW TONIGHT. SNOW COULD BE
MODERATE FOR A BRIEF TIME...ADDITIONAL SNOWFALL COULD BE UP TO 3
INCHES. TEMPERATURES WILL REMAIN MILD IN THE HIGH COUNTY UNDER A
PACIFIC AIRMASS.

OVER NORTHEAST COLORADO...THE ARCTIC AIRMASS IS EXPECTED TO REMAIN
IN PLACE THROUGH TONIGHT AS EASTERLY WINDS AROUND A SURFACE HIGH
OVER THE PLAINS KEEPS THE COLD AIR IN PLACE. FLURRIES WILL REMAIN
POSSIBLE THROUGH THE MORNING. EXPECT A SHARP TEMPERATURE CONTRAST IN
THE LOWER FOOTHILLS. THE TOP OF THE ARCTIC AIRMASS IS AROUND 7000-
7500 FEET MSL. SO PORTIONS OF THE FOOTHILLS...LIKE ESTES PARK...MAY
SEE LOWER 40S TODAY. MEANWHILE UNDER THE ARCTIC AIR...HIGHS WILL
ONLY BE IN THE TEENS AND LOWER 20S. SOME SINGLE DIGIT HIGHS WILL BE
POSSIBLE OVER THE NORTHEAST CORNER OF COLORADO. LOW CLOUDS WILL
PERSIST THROUGH THE MORNING AND MAY CONTINUE THROUGH DAY OVER THE
EASTERN PLAINS. THE ARCTIC AIR WILL START TO RETREAT TONIGHT AS A
SURFACE TROUGH FORMS OVER THE PLAINS AND WESTERLY WINDS SPREAD EAST
FROM THE FOOTHILLS FLUSHING OUT THE COLD AIR.

.LONG TERM...SHALLOW ARCTIC AIR CRADDLED IN THE SOUTH PLATTE
RIVER VALLEY DOWNSTREAM FROM GREELEY EARLY MONDAY MORNING MAY BE
ACCOMPANIED BY AREAS OF LOW CLOUD/STRATUS AND PATCHY FOG. LATER
THAT MORNING MODELS SHOW THE ARCTIC AIR FINALLY FLUSHING OUT OF
THE STATE WITH LIGHT DOWNSLOPE/DOWNVALLEY FLOW. OTHERWISE MOSTLY
CLEAR/PARTLY CLOUDY SKIES WITH WEAK MID-LEVEL SUBSIDENCE AND
DRYING TO START THE DAY OUT FLIPS TO WEAK SYNOPTIC SCALE ASCENT
WITH THE PASSAGE OF A WEAK MID-LEVEL SHORTWAVE TROUGH LATE IN THE
DAY. SHOULD SEE CLOUDS INCREASE THE MTNS THROUGHOUT THE DAY WITH
SCATTERED SNOW SHOWERS DEVELOPING BY LATE MORNING. NEW SNOW
ACCUMULATION IN THE HIGH COUNTRY SHOULD BE ON THE LIGHT
SIDE...GENERALLY IN THE 1-3 INCH RANGE BY EVENING...AND MAINLY
ALONG AND WEST OF THE CONTINENTAL DIVIDE. MEANWHILE EAST OF THE
MTNS SKIES SHOULD BEGIN TO FILL WITH MID AND HIGH CLOUDS DURING
THE LATE MORNING AND AFTERNOON HOURS AHEAD OF THIS FAST MOVING
DISTURBANCE. WHILE THAT/S GOING ON...A DRY SOUTH-SOUTHWEST LOW-
LEVEL FLOW ON THE PLAINS SHOULD WARM TEMPS TO LEVELS NEAR OR
SLIGHTLY ABOVE AVERAGE. AVERAGE HIGH AT DENVER ON MONDAY IS 51.
MAX TEMPERATURES PROVIDED BY MODEL GUIDANCE APPEAR A BIT TOO HIGH
GIVEN THE COOLING ALOFT AND INCREASING CLOUD COVER. MODELS SHOW
THIS DISTURBANCE QUICKLY EXITING THE AREA MONDAY EVENING WITH THE
FLOW ALOFT BECOMING NORTHWESTERLY. SUCH A FLOW AND WEAK COLD AIR
ADVECTION SHOULD CONTINUE TO PRODUCE AREAS OF LIGHT SNOWFALL ON
WEST FACING MTN SLOPES OVERNIGHT. ANY ADDITIONAL ACCUMULATION
SHOULD BE ON THE VERY LIGHT SIDE. OTWS...TEMPERATURES OVERNIGHT
SHOULD BE ON THE MILD SIDE ESPLY IN AND NEAR THE FRONT RANGE
FOOTHILLS DUE TO ENHANCED DOWNSLOPE/DOWNVALLEY FLOW.

ON TUESDAY...WARMUP CONTINUES WITH WEAK RIDGING ALOFT AND DOWNSLOPE
FLOW EAST OF THE MTNS. HOWEVER...FAST NORTHWEST FLOW ALOFT WHISKS IN
ANOTHER WAVE WHICH MODELS SHOW PASSING OVER THE FCST AREA TUESDAY
NIGHT. MODELS HAVE BEEN CONSISTENT IN SHOWING THE PASSAGE OF THIS
WAVE. IN ADDITION...MOST MODELS SHOW A COLD FRONT AT THE SFC
DROPPING OUT OF WYOMING AND ACRS NORTHEAST COLORADO LATE IN THE
AFTERNOON. THIS BNDRY COULD SERVE AS A FOCUS FOR SHOWER DVLPMNT ACRS
THE NORTHEAST CORNER OF THE CWFA AFTER 21Z. PCPN SHOULD MOSTLY BE
RAIN WITH TEMPERATURES IN THE UPPER 40S/LOWER 50S AT THAT TIME.
TOWARDS EVENING MODELS SHOW A 60-80KT JETLET STREAKING EASTWARD OVER
THIS SAME AREA PROVIDING ADDITIONAL LIFT FOR SHOWER/PCPN
DEVELOPMENT. FOR THAT REASON..UPPED POPS IN THE NORTHEAST ZONES
42..48..49..50 AND 51 DURING THE LATE AFTERNOON AND EARLY EVENING
HOURS. NAM AND GFS INDICATE A NARROW SWATH OF 1-3 INCH SNOW
ACCUMULATION ALONG THE WYO/NEB/COLO BORDER. WILL HOLD OFF FOR NOW
AND WAIT TO SEE WHAT NEXT MODEL RUN INDICATES. LATER THAT NIGHT
WAVE MOVES OUT WITH CLEARING IN ITS WAKE.

WEDNESDAY AND THURSDAY...UPPER RIDGE BUILDING OUT WEST SHIFTS EAST
OVER COLORADO DURING THIS PERIOD...RESULTING IN FEW IF ANY SNOW
SHOWERS IN THE HIGH COUNTRY...LIGHT WINDS AND TEMPERATURES WELL
ABOVE AVERAGE...PARTICULARLY ON THURSDAY. COULD SEE AFTERNOON
READINGS NUDGING THE 70 DEG MARK IN THE DENVER AREA...WITH 60S ON
THE PLAINS AND MAINLY 40S/LOWER 50S IN THE HIGH COUNTRY...I.E.
SPRING SKIING CONDITIONS.

LOOKING AHEAD TO FRIDAY AND THE WEEKEND...THE NEXT WEATHER SYSTEM
DIVING DOWN FROM THE NORTHERN ROCKIES IS STILL FORECAST TO IMPACT
THE FORECAST AREA ON FRIDAY IN TWO PARTS. LATEST MODEL CONTINUE TO
TREND WEAKER WITH THE FRONT SIDE OF THIS SYSTEM PASSING BY ON
FRIDAY. MOISTURE AND ENERGY WITH THE SECOND PART OF THIS WAVE
PASSING OVER THE AREA FRIDAY NIGHT APPEARS DEEPER AND STRONGER...
RESPECTIVELY. A COLD FRONT ACCOMPANIES THIS SECOND LOBE OF ENERGY.
PRECIP CHANCES WITH THIS LATE WEEK SYSTEM LOOKS BETTER AND COOLING
MORE PRONOUNCED ASSUMING IT REMAINS IN INTACT. THE WEEKEND LOOKS DRY
AND WARMER WITH AN UPPER RIDGE BUILDING OVER THE WESTERN CONUS.

&&

.AVIATION...LOW CLOUDS ARE EXPECTED TO PREVAIL THROUGH AT LEAST 18Z
WITH CEILINGS OF 500 TO 1500 FEET. THERE WILL BE A CHANCE FOR FOG
WITH VISIBILITY LESS THAN A MILE AND CEILINGS BELOW 500 FEET FROM 12-
16Z. THE LOW CLOUDS ARE EXPECTED TO LIFT AND SCATTERED OUT FOR A
TIME AFTER 18Z...BUT WILL LIKELY REFORM AFTER 00Z. WESTERLY WINDS
DEVELOP LATE THIS EVENING AND FLUSH OUT THE LOWER CLOUDS AROUND
06Z.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
WIND CHILL ADVISORY UNTIL 11 AM MST THIS MORNING FOR COZ042-044-
048>051.

&&

$$

SHORT TERM...MEIER
LONG TERM....BAKER
AVIATION...MEIER