000 
FXUS64 KMAF 291117
AFDMAF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MIDLAND/ODESSA TX
617 AM CDT FRI MAY 29 2009

.AVIATION...
VFR CONDITIONS AND LIGHT MAINLY EAST WINDS TO PERSIST THROUGH
TONIGHT OUTSIDE OF ISOLATED TO SCATTERED THUNDERSTORM ACTIVITY.
THE BETTER CHANCES FOR AFTERNOON AND EVENING THUNDERSTORMS WILL
EXIST WEST OF THE PECOS RIVER NEAR THE KCNM AND KFST TERMINALS.

&&

.PREV DISCUSSION... /ISSUED 458 AM CDT FRI MAY 29 2009/ 

DISCUSSION...
EARLY MORNING WATER VAPOR/RUC COMBO SHOWING WEAK SUBTROPICAL
RIDGING MOVING ACROSS THE REGION AT THE PRESENT TIME WITH LONGWAVE
POLAR JETSTREAM RIDGING CONTINUING TO BUILD ACROSS THE
INTERMOUNTAIN WEST. WEAK CUT-OFF LOW REMAINS POSITIONED ACROSS THE
SOUTHERN CA COAST/NORTHERN BAJA PENINSULA. ALL INDICATIONS POINT
TOWARDS ANOTHER ROUND OF AFTERNOON CONVECTION AS UPSLOPE LOW-LEVEL
FLOW CONTINUES TO DOMINATE. WRF12 HINTS AT AN INVERTED SURFACE
RIDGE EXTENDING SOUTHEAST INTO THE AREA BY AFTERNOON FROM THE
CENTRAL NM MOUNTAINS. THIS FEATURE IN COMBINATION WITH ANOTHER
SURFACE HIGH ACROSS EASTERN OK/LWR MISS RVR VLY WILL ENHANCE
SOUTHEASTERLY UPSLOPE FLOW THROUGH THE AFTERNOON. WRF12 CONTINUES
TO PRODUCE PRECIP MAINLY WEST AND SOUTHWEST OF SAID RIDGE AXIS AND
GENERALLY HAVE FOLLOWED THESE TRENDS FOR TODAY/S FORECAST. BASED
ON CONSISTENCY AND PERFORMANCE OF THE WRF12 IN RECENT DAYS...FEEL
BEST CONVECTION POTENTIAL WILL ONCE AGAIN RESIDE ALONG THE HIGHER
ELEVATION TERRAIN SURFACES OUT WEST WHERE DAYTIME HEATING WILL
COMBINE WITH A WEAK SUBTROPICAL SHORTWAVE ORIGINATING FROM THE
CUT-OFF LOW OUT WEST. AS OPPOSED TO YESTERDAY...LOW-LEVEL
CONVERGENCE FIELDS SUGGEST NO REAL DEFINABLE INITIATION AREAS LENDING
SUPPORT THAT ACTIVITY WILL LIKELY BE CONFINED TO THE HIGHER
ELEVATION SURFACES ORIGINALLY WITH EVENTUAL EASTWARD PROGRESS
INTO THE PLAINS BY LATE AFTERNOON EARLY EVENING. BEST SHEAR (0-6KM
BULK SHEAR APPROACHING 30 KTS) WILL RESIDE ACROSS THE TX BIG
BEND/MARFA PLATEAU AREAS AND IF ANY SEVERE STORMS DEVELOP...CAN
EXPECT THE MOST ROBUST ACTIVITY CONFINED TO THESE AREAS...HOWEVER
NOT OVERLY CONFIDENT ON SEVERE POTENTIAL BASED ON WEAK LOW/MID-
LEVEL LAPSE RATES AND ONLY MODEST MLCAPE VALUES (UNDER 1000 J/KG).
BEST INSTABILITY EXPECTED TO RESIDE WELL WEST OF THE REGION ACROSS
NORTH-CENTRAL MEXICO IN CLOSE PROXIMITY TO A WELL DEVELOPED 
MID-LEVEL THETA-E RIDGE AXIS. IN ANY EVENT...CAN EXPECT T-STORM
DEVELOPMENT HOWEVER DEGREE OF SEVERITY REMAINS IN QUESTION BASED
ON REASONING LISTED ABOVE.

BY TONIGHT...SHOWERS/STORMS WILL COME TO AN END RATHER QUICKLY
WITH LOSS OF DAYTIME HEATING. RATHER WEAK WINDS EXPECTED OVERNIGHT
AS SURFACE HIGH ACROSS EASTERN OK SINKS SOUTH INTO EASTERN TX. A
NOTABLE WARMING TREND INITIATES ACROSS THE AREA BEGINNING TOMORROW
AS THE ROCKY MOUNTAIN RIDGE AXIS MIGRATES EASTWARD. CONTINUED
SLIGHT CHANCE MENTION FOR SHOWERS/STORMS ACROSS THE HIGHER
ELEVATION SURFACES OUT WEST IN RESPONSE TO A BUILDING MID-LEVEL
THETA-E/INSTABILITY AXIS BY AFTERNOON ALONG WITH EXPECTED DAYTIME
HEATING. MEAN UPPER RIDGE TO BEGIN BREAKING DOWN BY SUN AS CA 
CUT-OFF LOW TRANSLATES INTO THE INTERMOUNTAIN WEST/CENTRAL
ROCKIES. SOUTHERLY LOW-LEVEL FLOW TO STRENGTHEN AS A LEESIDE LOW
BECOMES ESTABLISHED ACROSS THE KS/CO HIGH PLAINS. CAN EXPECT
WARM/SLIGHTLY ABOVE AVERAGE TEMPS SUN AFTERNOON AS A RESULT. WARM
TEMPS TO CONTINUE INTO EARLY NEXT WEEK AS THE SFC LOW SLOWLY SINKS
SOUTH INTO THE TX/OK PANHANDLE REGION BY MON. ECMWF/GFS IN GOOD
AGREEMENT THAT A DRYLINE WILL BEGIN TAKING SHAPE BY MON IN ADVANCE
OF SOUTHWARD MOVING TX/OK PANHANDLE LOW. WESTERLY DOWNSLOPE FLOW
TO BECOME FIRMLY ESTABLISHED EARLY NEXT WEEK ALONG WITH A
STRENGTHENING H85 THERMAL RIDGE. HAVE RAISED TEMPS IN RESPONSE FOR
BOTH MON/TUE. GFS/ECMWF CONTINUE TO SUGGEST FRONTAL BOUNDARY
SAGGING SOUTH INTO OUR AREA BY WED WITH COOL NORTHEASTERLY FLOW
POSSIBLE THROUGHOUT THE DAY. NEW 00Z ECMWF JUST ARRIVED WITH
CONTINUED SUPPORT FOR THIS SCENARIO AND BASED ON THIS HAVE TRIMMED
TEMPS ACROSS THE NORTH SLIGHTLY. DECIDED TO ONLY MAKE MODEST TEMP
ADJUSTMENTS FOR BOTH WED/THU AS SOME MODEL DISAGREEMENTS REMAIN
WITH STRENGTH OF COOLER AIR AND HOW LONG IT WILL RESIDE ACROSS THE
AREA. TOWARDS THE CONCLUSION OF THE WEEK...UPPER RIDGING TO BECOME
MORE ESTABLISHED AS AS A REX BLOCK DEVELOPS OFF THE WEST COAST. AS
A RESULT...CAN EXPECT WARMING TEMPS ONCE AGAIN AND HAVE RAISED
TEMPS SLIGHTLY.

&&

.MAF WATCHES/WARNINGS/ADVISORIES...
NM...NONE.
TX...NONE.

&&

$$

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