Tuesday, March 23, 2010

MESO: Mesoscale Discussion 0207

ACUS11 KWNS 240022
SWOMCD
SPC MCD 240021
COZ000-NMZ000-240615-

MESOSCALE DISCUSSION 0207
NWS STORM PREDICTION CENTER NORMAN OK
0721 PM CDT TUE MAR 23 2010

AREAS AFFECTED...PORTIONS CO ADJACENT AND PARALLEL TO FRONT
RANGE...INCLUDING PALMER DIVIDE AND RATON MESA AREAS...SMALL PORTION
NERN NM.

CONCERNING...HEAVY SNOW

VALID 240021Z - 240615Z

SNOW LEVELS FCST TO CONTINUE LOWERING IN ELEVATION THROUGH REMAINDER
EVENING WITH RAIN CHANGING QUICKLY TO SNOW...AND OCCASIONAL HEAVY
SNOW EXPECTED. THIS TREND WILL SHIFT/SPREAD BOTH FROM FOOTHILLS
ONTO ADJACENT PLAINS...AND ALSO IN N TO S MANNER ALONG I-25 CORRIDOR
FROM DEN AREA SWD TOWARD PUB LATER THIS EVENING. BETWEEN
04Z-06Z...LOWERING FREEZING LEVELS...UPSLOPE ASCENT AND INCREASING
SNOW RATES COULD REACH AREAS OF CO/NM BORDER FROM RTN EWD AS WELL.
RATES GENERALLY 1-2 INCHES/HOUR ARE EXPECTED BUT WITH EMBEDDED BANDS
AND BURSTS LOCALLY PRODUCING RATES 2-3 INCHES/HOUR.

MID-UPPER LEVEL CYCLONE -- EVIDENT IN MOISTURE CHANNEL IMAGERY OVER
W-CENTRAL CO -- WILL MOVE SEWD ACROSS WRN CO THROUGH 6Z. STRONGEST
JUXTAPOSITION OF LARGE-SCALE ASCENT ALOFT AND LOW-MIDLEVEL LIFT
ACCOMPANYING WAA AND FRONTOGENETIC REGIME LIKEWISE WILL SHIFT SSEWD
FROM NRN PORTIONS FRONT RANGE ACROSS DISCUSSION AREA. DEN AREA VWP
ALREADY SHOWS LAYER OF ELYS WITHIN LOWEST KM...WITH LOCALLY ENHANCED
ASCENT LIKELY ABOVE COMBINED FRONTAL/OUTFLOW AIR MASS FROM
CONVECTION THAT MOVED ACROSS DEN AREA DURING PAST COUPLE HOURS.
ELYS SHOULD BACK TO NELYS THEN NNELYS WITH TIME...FOCUSING STRONGEST
UPSLOPE LIFT AND HEAVIER OROGRAPHIC SNOWS EWD FROM HIGHER ELEVATIONS
DOWN ACROSS PORTIONS OF LOWER FOOTHILLS...PALMER DIVIDE...AND
ESPECIALLY THAT AREA NEAR THEIR INTERSECTION. SIMILAR PROCESS IS
EXPECTED TO BEGIN A FEW HOURS LATER -- APCHG 6Z...ALONG PORTIONS RTN
MESA REGION. RUC/SREF GUIDANCE REASONABLY INDICATES STRONGEST
LOW-LEVEL FRONTOGENETIC FORCING SHIFTING SWD ACROSS THIS CORRIDOR AS
WELL...IN STEP WITH MOVEMENT OF MID-UPPER LOW. MODIFIED DNR RAOB
AND TIME SERIES OF RUC SOUNDINGS AT VIRTUALLY ANY LOCATION IN THIS
CORRIDOR REASONABLY DEPICT WHOLE-COLUMNAR COOLING WITH
TIME...REDUCTION OF SNOW LEVELS TO SFC...AND STRENGTHENING ASCENT
WITHIN THERMALLY CONDUCIVE DENDRITIC GROWTH LAYERS. MAIN LIMITING
FACTOR MAY BE LACK OF MORE ROBUST MOISTURE IN UPSTREAM LOW-LEVEL
TRAJECTORIES...HOWEVER STRENGTH OF ASCENT/COOLING SHOULD MAXIMIZE
SNOW POTENTIAL FOR SOMEWHAT LIMITED MOISTURE CONTENT AVAILABLE.

..EDWARDS.. 03/24/2010

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...PUB...BOU...ABQ...

LAT...LON 37210477 37830494 39210522 39800534 40090531 40450503
40150412 39590348 39240344 38970369 38690422 38270453
37660440 37330403 36930347 36900441 37210477

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