|
| Mesoscale Discussion 493 |
|
< Previous MD
Next MD >
|
|
MESOSCALE DISCUSSION 0493
NWS STORM PREDICTION CENTER NORMAN OK
0217 AM CDT FRI APR 17 2009
AREAS AFFECTED...PARTS OF SERN WY / NRN CO FRONT RANGE FOOTHILLS AND
ADJACENT HIGH PLAINS
CONCERNING...HEAVY SNOW
VALID 170717Z - 171115Z
INTERMITTENT HEAVY SNOWFALL RATES UP TO 1 INCH/HR MAY DEVELOP AS
EARLY AS 09-12Z IN AREAS IMMEDIATELY ADJACENT TO CO FOOTHILLS NEAR/W
OF THE I-25 CORRIDOR AS CHANGEOVER OCCURS.
LATEST SURFACE ANALYSIS SHOWS A 1007 MB SURFACE LOW INVOF NERN NM
WITH A N-S ORIENTED STATIONARY FRONT ALONG THE CO FRONT RANGE THEN
EXTENDING NEWD TOWARDS THE NEB SANDHILLS. LATE EVENING SURFACE
TEMPS HAVE GENERALLY HELD IN THE LOWER TO MIDDLE 30S F OVER THE MCD
AREA TO THE W OF STATIONARY FRONT...WHEREAS LOCALES FURTHER N OVER
SERN WY ARE AOB FREEZING WITH 1-2 INCH/HR SNOWFALL RATES REPORTED
NEAR LAR DURING THE EVENING HRS.
WATER VAPOR IMAGERY SHOWS A MID-LEVEL VORTICITY MAXIMUM AND
ATTENDANT DRYSLOT MOVING NWD FROM NERN NM TOWARDS E-CNTRL CO.
INCREASING UVV/S ASSOCIATED WITH THIS FEATURE ALONG WITH LOW-MID
LEVEL FRONTOGENESIS AND UPSLOPE CONTRIBUTION WILL SUPPORT FOCUSED
ASCENT ACROSS THE REGION THROUGH MID-MORNING FRI. LATEST FORECAST
SOUNDING MODEL SUITE SUGGESTS THERMODYNAMIC PROFILES SUPPORTIVE OF A
RAIN TO SNOW CHANGEOVER BEGINNING GENERALLY AS EARLY AS THE 09-12Z
PERIOD AS HEAVIER PRECIP RATES SHIFT S FROM SERN WY INTO CO.
STEEPENING LAPSE RATES ASSOCIATED WITH AFOREMENTIONED MID-LEVEL
FEATURE AND OROGRAPHICAL FORCED ASCENT...MAY RESULT IN
CONVECTIVELY-ENHANCED PRECIP/SNOW RATES UP TO 1 INCH/HR WITH
LOCALIZED 2 INCH/HR POSSIBLE IN THE FOOTHILLS DURING THE MORNING
HRS.
..SMITH.. 04/17/2009
ATTN...WFO...PUB...BOU...
LAT...LON 39900559 40840542 40840500 39960494 39200466 38780487
38760520 39110539 39900559
|
|
Top/All Mesoscale Discussions/Forecast Products/Home
|
|