MESOSCALE PRECIPITATION DISCUSSION 0862
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
900 PM EDT WED OCT 04 2017

AREAS AFFECTED...SOUTHWEST OK...NORTH TX PANHANLE...EASTERN NM

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 050115Z - 050615Z

SUMMARY...STRENGTHENING WARM AIR ADVECTION/MOISTURE FLUX SHOULD
INCREASE CONVECTIVE COVERAGE AND RAINFALL EFFICIENCY THIS EVENING
POSSIBILY OVER AREAS SATURATED FROM LAST NIGHT'S HEAVY RAINFALL.

DISCUSSION...A SLOW BUT STEADY INCREASE IN CONVECTIVE VIGOR HAS
BEEN NOTED BOTH IN REGIONAL RADAR MOSAIC AS WELL AS PERCOLATING
COOLING IR TOPS ACROSS THE EASTERN N TX PANHANDLE INTO SW OK. 
THIS IS IN RESPONSE TO STRENGTHENING WAA REGIME AS NOCTURNAL LLJ
BEGINS TO ENHANCE FROM 10 TO 20KTS TO EVENTUALLY 30KTS TOWARD
04-05Z.  CELLS ARE CURRENTLY CONFINED TO THE EASTERN QUADRANT LLJ
WHERE THERE IS INCREASED LOW LEVEL MOISTURE CONVERGENCE MAINLY DUE
TO CONFLUENCE FROM EASTERN EDGE OF DEEPEST MOISTURE/INSTABILITY
OVER NW TX AS MID-LEVEL DRY AIR/DEEP ANTICYCLONE UNDERCUTS THE
DEEP MOISTURE CHANNEL ACROSS OK.  PARAMETERS STILL REMAIN ABOUT 2"
FOR TPW AND 750-1000 J/KG OVER THIS AREA...AND AS SUCH LOCALIZED
CONVECTIVE CORES STILL SUPPORT RATES UP TO 2-2.5"/HR POSING
CONTINUED LOCALIZED FLASH FLOOD RISK. 

SFC BASED CONVECTION HAS BEEN DEVELOPING FAIRLY FAR SOUTH OF THE
STATIONARY FRONT FROM END TO HFF.  A SUBTLE WAVE LIFTING OUT OF
NM/S CO SUPPORTING A NW-SE WARM FRONT INTERSECTING THE BOUNDARY
AROUND BGD.  HOWEVER 00Z MESOANALYSIS DETECTS A WEAK BOUNDARY
LIKELY REINFORCED BY SOME DIFFERENTIAL HEATING/RAIN COOLING FROM
SW OK ACROSS CDS TO PVW TO CVS...THIS SHOULD CONTINUE TO REMAIN
THE FOCUS AS IT LIFTS NORTH/WASHES OUT WITH THE STRENGTHENING LLJ.
ADDITIONALLY...GOES-16 WV 6.9UM CHANNEL SHOWS MODEST DIFFLUENCE
OVER THE REGION THAT WILL SLOWLY DRIFT WESTWARD WITH TIME AS THE
2H RIDGE CONTINUES TO RETROGRADE ACROSS INTO N COAHUILA MEXICO
ALLOWING FOR GREATER EVACUATION ALOFT.

AS SUCH WAA INDUCED DEEPER CONVECTION WILL FURTHER STRENGTHEN FROM
EAST TO WEST ACROSS THE TX PANHANDLE FROM 01-03Z. AS CONVECTION
DOES DEVELOP...MEAN STEERING FLOW IS WSW TO ENE SUPPORTING SOME
POTENTIAL FOR CELLS TO CROSS TRACKS.  HOWEVER...EFFECTIVE BULK
SHEAR OF 30KTS WITH MODEST LOW LEVEL HELICITY...MAY SUPPORT SOME
ROTATION ALLOWING FOR RIGHT TURNING/SLOWING FORWARD  PROGRESS
ALONG THE BOUNDARY AND THEREFORE INCREASED LOCALIZED RAINFALL
TOTALS...AS WELL AS INCREASED MOISTURE FLUX TO THE CELL FOR
GREATER RAINFALL EFFICIENCY.  THE RECENT 22/23Z HRRR RUNS SEEM TO
TAKE THIS SCENARIO TO THE EXTREME SUGGESTING TOTALS OF 3-6" OVER A
LARGE AREAL SWATH NEAR/NORTH OF I-40 IN TX; THIS SEEMS UNLIKELY
AND WOULD FAVOR A MORE TEMPERED (THOUGH STILL POSSIBLY UNDERDONE)
ARW2/NSSL-WRF OR EVEN THE 18Z 27KM GFS. 

TOWARD 03-05Z...SUPERCELLS CURRENTLY CROSSING I-25 IN CENTRAL NM
WILL ADVANCE WITH WEAK MID-LEVEL TROF/HEIGHT FALLS.  SURFACE WIND
SHOULD BACK AND INCREASE IN RESPONSE TO IT ACROSS E
NM...SUPPORTING STRENGTHENED SFC MOISTURE CONVERGENCE.  THIS
SHOULD BE GENERALLY LOCATED VERY NEAR AREAS AFFECTED BY LAST
EVENING'S CONVECTIVE COMPLEX.  GROUND CONDITIONS ARE ALREADY
SATURATED/NEARLY SATURATED (80-100%) PER WATER MODEL/HRRR SOIL
CONDITIONS AND WHILE DEEP MOISTURE VALUES ARE SLIGHTLY LOWER (TPWS
OF 1.3-1.5") RATES OF 1.5-2"/HR ARE LIKELY TO EXCEED THE
COMPROMISED GROUND CONDITIONS MAKING FLASH FLOODING MORE LIKELY AT
OR AROUND 05-07Z. 

GALLINA

ATTN...WFO...ABQ...AMA...LUB...OUN...

ATTN...RFC...ABRFC...WGRFC...

LAT...LON   36150333 36120212 35910064 35799947 35569865
            34609875 34439933 34519993 34500120 34660201
            34800277 34670350 34390430 34440469 34670486
            34970475 35240485 35490511 36020482