Area Forecast Discussion
Issued by NWS

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451
FXUS64 KLUB 181750
AFDLUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
1250 PM CDT THU SEP 18 2014

.AVIATION...
TROPICAL MOISTURE PROFILE ACROSS THE AREA NEXT 24 HOURS WITH THE
REMAINS OF TS ODILE EXPECTED TO MOVE SLOWLY FROM SOUTHWEST TO
CENTRAL NEW MEXICO. IN ADDITION TO DEEP MOISTURE...THIS WILL FAVOR
DEEP LIFT AND PREVAILING RAIN AND THUNDER CHANCES FOR KLBB.
AIRMASS JUST WEST AND SOUTHWEST OF KLBB APPEARS TO BE QUICKLY
DESTABILIZING AGAIN EARLY THIS AFTERNOON AND SHOULD SUPPORT
INCREASING THUNDER CHANCES. A WESTWARD MOVING CONVECTIVE OUTFLOW
NOW IN WESTERN OKLAHOMA WILL MOVE THROUGH KCDS BY 20Z AND APPROACH
KLBB 22Z-00Z TIME FRAME WHICH ALSO SHOULD HELP ENHANCE THUNDER
CHANCES. DO NOT ANTICIPATE NECESSARILY CONTINUOUS PRECIPITATION
CHANCES AT KLBB BUT THE BREAKS ARE DIFFICULT TO SUPPORT OR TIME.
MORE STRATIFORM ENVIRONMENT SEEMS MORE LIKELY OVERNIGHT WITH LOW
CEILING AND VISIBILITY RISK KLBB ESPECIALLY AND MOSTLY IFR
POSSIBLY LIFR CONDITIONS. RMCQUEEN

&&

.PREV DISCUSSION... /ISSUED 1005 AM CDT THU SEP 18 2014/

UPDATE...
THE FLOOD WATCH HAS BEEN EXPANDED EASTWARD TO INCLUDE MOST OF THE
CWA...EXCLUDING HALL AND CHILDRESS COUNTIES. A LARGE AREA OF
MODERATE RAINFALL CONTINUES TO ENVELOP MUCH OF THE FA...WITH
POCKETS OF HEAVY RAIN. IT APPEARS THE HEAVIEST OF THE RAINFALL IS
GOING TO TEND TO CONVERGE ACROSS OUR SOUTHEAST ZONES OVER THE NEXT
COUPLE OF HOURS...AND FOR THIS REASON WE HAVE DECIDED TO EXPAND
THE FLOOD WATCH EASTWARD. POP...WEATHER AND QPF GRIDS WERE ALSO
ADJUSTED GIVEN CURRENT RADAR TRENDS AND HIGH RESOLUTION MODELS. A
MENTION OF HEAVY RAIN WAS ALSO ADDED TO A GOOD CHUNK OF THE AREA
THIS MORNING...WHILE MAINTAINING THE HEAVY RAIN MENTION ACROSS THE
SOUTHEAST ZONES THIS AFTERNOON. UPDATED PRODUCTS HAVE BEEN SENT.

PREV DISCUSSION... /ISSUED 630 AM CDT THU SEP 18 2014/

AVIATION...
FLYING WEATHER FOR VFR PILOTS WILL BE A DISAPPOINTMENT NEXT 24
HOURS. WIDESPREAD RAINFALL WITH EMBEDDED TSTMS WILL LIKELY PERSIST
MUCH OF THE FCST PERIOD. WE MAY SEE SOME PERIOD OF MVFR/VFR AT
KLBB BUT THIS IS LIKELY ONLY TO EXIST BETWEEN STORMS AS WIDESPREAD
RAINFALL IS EXPECTED THIS MORNING WITH PERHAPS AN AFTERNOON BREAK
THEN MORE AGAIN TONIGHT. IFR AIRCRAFT SHOULD BE IMPACTED MUCH LESS
HEAVILY THOUGH MANEUVERING AROUND CONVECTIVE CELLS WILL BE
NECESSARY.

PREV DISCUSSION... /ISSUED 322 AM CDT THU SEP 18 2014/

SHORT TERM...
INTERESTING SHORT TERM TO SAY THE LEAST.  H2 RIDGING IS NOTED ON NWP
INITIALIZATION AS WOULD BE EXPECTED ABOVE A VIBRANT TROPICAL
SYSTEM.  LOOKING AT H7 AND BELOW...WE SEE A CLOSED LOW STRUCTURE
/WHAT IS LEFT OF ODILE/ WORKING ITS WAY ACROSS SERN AZ.  STRONG
MOISTURE ADVECTION IS NOTED ALONG THE EAST SIDE OF THIS FEATURE AND
IS QUITE EVIDENT ON WV AS WELL AS RADAR IMAGERY.  IN FACT...THE TSTM
COMPLEX RUNNING FROM THE SIERRA DIABLO MTNS UP INTO THE SACRAMENTOS
IS RATHER HEALTHY FOR THIS TIME OF NIGHT.  IT IS FORMED ALONG ONE OF
THE BANDED FEATURES.  THE HRRR SEEMS TO BE ONTO SOMETHING AND HAD
CORRECTLY FORECAST THE ESTABLISHMENT OF RAIN SHOWERS ACROSS THE
NORTHERN SOUTH PLAINS.  IF THE TRENDS CONTINUE...AS THE SACRAMENTO
RANGE SYSTEM APPROACHES...WE SHOULD SEE WIDESPREAD RAINFALL DEVELOP
BEFORE 12Z ACROSS THE SOUTH PLAINS.  WILL CONTINUE TO MONITOR TRENDS
FOR AREAL FLOOD POTENTIAL.

LOOKING AHEAD AFTER 12Z...Q VECTOR ANALYSIS SUGGESTS DECENT LARGE
SCALE LIFT PERSISTING INTO THE EARLY AFTERNOON HOURS ESPECIALLY WEST
OF THE ESCARPMENT.  THIS FORCING APPEARS TO WANE DURING THE LATE
AFTERNOON AND EVENING BEFORE RETURNING...ALBEIT MORE
WEAKLY...OVERNIGHT.  HOWEVER...MODEST DIURNAL HEATING AND COOLING OF
THE MID LEVEL SHOULD ALLOW FOR LONG/SKINNY CAPE WHICH SHOULD KEEP
LIGHT TO MODERATE CONVECTION GOING THROUGH THE AFTERNOON HOURS.
SO...BOTTOM LINE...WILL CONTINUE TO RAISE POPS ACROSS THE AREA WITH
MOST AREAS CATEGORIZED AS LIKELY.  IN REVIEWING NWP DERIVED QPF AND
HPC FCST FIELDS...THIS ASSESSMENT SEEMS TO MATCH UP WELL.

WHILE IT SEEMS TO BE VERY WET THIS SEPTEMBER IN LUBBOCK WITH MANY
DAYS OF RAINFALL...WE ARE STILL ONLY ABOUT ONE QUARTER OF THE WAY TO
THE RECORD RAINFALL OF 2008 WHERE 8.7 INCHES FELL.  STILL...WITH
MANY MORE DAYS OF RAINFALL STARING AT US LATER THIS WEEK...WE COULD
SEE THIS CHALLENGED.

GIVEN THE STRONG SIGNAL FOR A PROTRACTED RAIN EVENT...HAVE ELECTED
TO ISSUE AREAL FLOOD WATCH FOR THE COUNTIES GENERALLY WEST OF THE
ESCARPMENT THROUGH 00Z SATURDAY.  IT IS ANTICIPATED THAT THIS MAY
HAVE TO BE EXTENDED EASTWARD LATER IN TIME BUT WANT RAISE AWARENESS
THAT THE NEXT FEW DAYS COULD POSE SOME HYDROLOGIC PROBLEMS.
THOUGH...WE CAN USE THE RAIN AFTER THE DEFICIT SINCE LATE 2010.

LONG TERM...
REMNANTS OF ODILE WAS LOCATED ACROSS SERN AZ/SWRN NM EARLY THIS
MORNING...WITH THE UA RIDGE CENTERED ACROSS ERN OLD MEXICO GUIDING
ODILE/S REMNANTS ENE TO ACROSS THE DESERT SW. CONTINUED AMPLE
MOISTURE PROVIDED BY ODILE AND THE GULF OF MEXICO HAVE WILL RESULT
IN PWATS INCREASING INTO THE 1.50-2.10 INCH RANGE ACROSS THE CWA
TOMORROW THROUGH EARLY WEEKEND...AS THE SAID DISTURBANCE GRADUALLY
PASSES ACROSS THE REGION. BOTH THE NAM AND GFS EXHIBITS THE TRACK OF
THE DISTURBANCE TO MOVE ENE ACROSS NERN NM/WRN PANHANDLES TOMORROW
EVENING...TO ACROSS THE CENTRAL PLAINS LATE TOMORROW NIGHT/EARLY
SATURDAY MORNING WITH A CONTINUED EWRD PROGRESSION /THUS EXITING THE
REGION/. THE CURRENT ECMWF RUN IS QUITE A BIT DIFFERENT FROM THE
PREVIOUS SOLUTIONS AS IT NOT ONLY MOVES THE DISTURBANCE ALMOST
SQUARELY ACROSS THE CWA TOMORROW NIGHT...IT THEN BECOMES
QUASI-STATIONARY THROUGH TUESDAY MORNING WHERE THEREAFTER IT
COMMENCES TO SHIFT EAST OF THE REGION. THE OBVIOUSLY SLOWER ECMWF
SOLUTION WOULD MEAN SHOWERS AND THUNDERSTORMS /WITH MODERATE TO
HEAVY RAINFALL/ LASTING THROUGH TUESDAY MORNING AS AN UPSLOPE SFC
REGIME ENCOMPASSES THE AREA. THIS FORECAST PACKAGE WILL LEAN TOWARDS
THE GFS SOLUTION ATTM...GIVEN IT IS A BIT MORE PERSISTENT FROM MODEL
RUN TO MODEL RUN. THIS WOULD MEAN THAT THE THREAT FOR MODERATE TO
HEAVY RAINFALL MOVING WEST TO EAST WITH TIME...WILL BE BEST FRIDAY
THROUGH SATURDAY MORNING...THUS COINCIDING WITH WHEN THE
DISTURBANCE PASSES NE TOWARDS THE CENTRAL PLAINS. SRLY FLOW AT THE
SFC WILL VEER TO THE NORTH LATE SATURDAY NIGHT COURTESY OF A COLD
FRONTAL PASSAGE /WHICH IS NO LONGER SHOWN VIA THE ECMWF SOLUTION/.
THIS COLD FRONT WILL PROVIDE FOR ADDITIONAL PRECIP CHANCES THROUGH
SUNDAY...WITH A NOTABLE DECLINE NORTH TO SOUTH.

AS AN UA RIDGE MOVES OVERHEAD ON MONDAY...DRYER AIR WILL FILTER IN
AND PROMOTE TOP-DOWN DRYING...WHICH IS THE REASON FOR PWATS
DECLINING A BIT FROM NORTH TO SOUTH THOUGH...AMOUNTS OF 1.00-1.30
INCHES WILL ENDURE.  SFC WINDS WILL VEER TO A MORE UPSLOPE SFC
REGIME ON TUESDAY HENCE CAUSING PWATS TO JUMP BACK UP A BIT.
ATTENTION QUICKLY TURNS TO AN UA LOW CURRENTLY OFF THE COAST OF NRN
CA/OR...THAT IS SET TO WEAKEN WHILST PROGRESSING ENE ACROSS THE
CENTRAL ROCKIES EARLY NEXT WEEK...TO ACROSS PANHANDLE REGION/CENTRAL
PLAINS. ADEQUATE ATMOSPHERIC MOISTURE AND INCREASING UL SUPPORT MAY
LEAD TO ANOTHER SHOT AT PRECIP. WILL THEREFORE MAINTAIN MENTIONABLE
POPS ON TUESDAY. WILL OF COURSE NEED TO KEEP AN EYE ON HOW ODILE/S
REMNANTS WILL IN FACT BEHAVE BECAUSE IF THE ECMWF IS CORRECT...POPS
WILL DEFINITELY NEED TO BE RAMPED UP TOWARDS THE END OF THE EXTENDED
FORECAST.

ANTICIPATED CLOUD COVER AND RAINFALL WILL LEAD TO TEMPS 5-7 DEGREES
BELOW SEASONAL NORMS /70S AND 80S/ WITH OVERNIGHT LOWS IN THE 50S
AND 60S.

&&

.PRELIMINARY POINT TEMPS/POPS...
FRIONA        63  74  61  82  59 /  60  70  60  30  30
TULIA         64  77  63  80  62 /  50  70  60  50  30
PLAINVIEW     64  77  63  80  62 /  60  70  60  50  30
LEVELLAND     65  76  63  81  63 /  70  70  60  40  40
LUBBOCK       67  77  66  81  65 /  70  70  60  50  40
DENVER CITY   66  78  64  84  63 /  70  70  60  40  40
BROWNFIELD    67  78  64  83  64 /  70  70  60  40  40
CHILDRESS     67  83  67  80  66 /  50  50  60  60  40
SPUR          67  80  65  82  66 /  60  50  60  50  50
ASPERMONT     69  85  69  85  68 /  60  50  60  50  50

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
FLOOD WATCH THROUGH FRIDAY EVENING FOR THE FOLLOWING ZONES:
TXZ021>024-027>044.

&&

$$

99/99/05

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