Area Forecast Discussion
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000
FXUS64 KLUB 161057
AFDLUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
557 AM CDT THU APR 16 2015

.AVIATION...
VFR CONDITIONS EXPECTED THROUGH THE PERIOD FOR ALL SITES UNLESS
SHOWERS AND THUNDERSTORMS LATER THIS AFTERNOON/EVENING PASS
DIRECTLY OVER THE TERMINALS. KCDS HAS BEST CHANCE OF A
THUNDERSTORM PASSING OVERHEAD AS EARLY AS 22Z WITH SHOWERS AND
THUNDERSTORMS EXPECTED IN THE AREA THROUGH MIDNIGHT. VISIBILITIES
COULD DROP INTO MVFR FOR A SHORT PERIOD OF TIME IN THE STRONGEST
SHOWERS. HAIL UP TO HALF DOLLAR SIZE IS ALSO POSSIBLE WITH ANY OF
THE STRONGEST STORMS AFFECTING KCDS. KPVW AND KLBB HAVE POTENTIAL
FOR SIMILAR SEVERE WEATHER THIS AFTERNOON WITH GUSTY WINDS AND
QUARTER SIZE HAIL BEING PRIMARY THREAT AFTER 21Z.

&&

.PREV DISCUSSION... /ISSUED 443 AM CDT THU APR 16 2015/

SHORT TERM...
VORT MAX EMBEDDED IN SHORTWAVE EJECTING OUT OF NEW MEXICO INTO WEST
TEXAS RESPONSIBLE FOR ONGOING ISOLATED SHOWERS AND THUNDERSTORMS
ACROSS THE SOUTHERN TEXAS PANHANDLE AND NORTHERN SOUTH PLAINS SHOULD
SUPPORT ACTIVITY THROUGH PRE-DAWN HOURS. EXPECT THEM TO TAPER OFF BY
SUNRISE AS UPPER LEVEL ENERGY TRANSLATES NORTHEAST. ONGOING
CONVECTION IS ISOLATED AND WEAK...THEREFORE NOT ANTICIPATING ANY
STABILIZING EFFECT OUT AHEAD OF DRYLINE CONVECTION EXPECTED LATER
THIS AFTERNOON AND EVENING...IN FACT OUTFLOW BOUNDARIES CURRENTLY
VISIBLE ON RADAR COULD SERVE AS INITIATION POINTS FOR CONVECTION
THIS AFTERNOON/EVENING.

CONVECTIVE INITIATION ALONG THE DRYLINE IS EXPECTED LATER THIS
AFTERNOON AS A SURFACE LOW IN NORTHEAST NEW MEXICO DEEPENS THROUGH
THE AFTERNOON...WITH BULK SHEAR VALUES BETWEEN 30-40KTS...SURFACE
CAPE VALUES BETWEEN 1000-1500J/KG AND A WEAKLY CAPPED ENVIRONMENT
WITH 700MB TEMPS IN LOW SINGLE DIGITS CELSIUS...STRONGEST UPDRAFTS
SHOULD HAVE LITTLE DIFFICULTY IN PRODUCING SUPERCELLS CAPABLE OF
SEVERE LEVEL WIND GUSTS...UP TO HALF-DOLLAR SIZE HAIL AND POSSIBLY
ISOLATED TORNADOES...HODOGRAPHS ALSO FAVOR THIS SCENARIO...BUT WITH
RELATIVELY HIGH LCL/S ANY TORNADOES WOULD BE ON THE LOW END OF EF-
SCALE.

DECENT CONSENSUS IN SHORT TERM GUIDANCE...ALONG WITH CIPS ANALOG
GUIDANCE PROVIDING CONFIDENCE...OF A DRYLINE FORMING THAT WILL
EXTEND FROM SOUTH CENTRAL TEXAS PANHANDLE SOUTHWARD THROUGH THE
SOUTH PLAINS...PRIMARILY JUST TO THE EAST OF LUBBOCK. SPC HAS ISSUED
AN ENHANCED DAY 1 RISK THAT HAS SHIFTED SLIGHTLY EAST AND NORTH FROM
PREVIOUS UPDATES...AND CURRENTLY COVERS THE SOUTHEAST TEXAS
PANHANDLE...NORTHEAST SOUTH PLAINS AND NORTHERN ROLLING PLAINS.

STORMS SHOULD BEGIN TO DEVELOP SOON AFTER 21Z WITH PEAK
HEATING...APPROX IN THE MID/UPPER 70S...AND ALSO COINCIDING WITH AN
UPPER LEVEL SHORTWAVE EJECTING OUT OF NEW MEXICO THAT TRANSECTS THE
DRYLINE AROUND THIS TIME. AS MENTIONED BEFORE...THE STRONGEST
UPDRAFTS SHOULD HAVE LITTLE DIFFICULTY INTENSIFYING INTO
SUPERCELLS IN THE CORRIDOR OF BEST INSTABILITY WHICH AT THIS TIME
WOULD EXTEND FROM CROSBY COUNTY EAST THROUGH KING COUNTY AND
NORTHWARD THROUGH BRISCOE AND CHILDRESS COUNTY. AS THE STORMS
EVOLVE AND THE DRYLINE BEGINS TO RETREAT WESTWARD INTO THE EVENING
MORE SHOWERS AND THUNDERSTORMS MAY BACK BUILD TO THE SOUTH AND
WEST...THESE STORMS MAY ALSO HAVE SEVERE POTENTIAL BUT MAINLY WITH
SEVERE WIND GUSTS AND HAIL. LATEST INTERMEDIATE 6Z GUIDANCE HINTS
AT A WEAK SQUALL LINE DEVELOPING BEHIND THE FIRST WAVE OF
THUNDERSTORMS DURING THE OVERNIGHT HOURS...WILL HAVE TO WAIT AND
SEE HOW THE DRYLINE CONVECTION EVOLVES BEFORE HAVING MUCH
CONFIDENCE IN THAT SCENARIO.

LONG TERM...
THE UA LOW WAS NOTED ACROSS THE FOUR-CORNERS REGION EARLY THIS
MORNING...AND THUS UL SUPPORT HAS BEEN GRADUALLY INCREASING VIA
LIGHT SCATTERED SHOWERS THAT HAVE MOVED EAST FROM THE ERN NM TO
ACROSS THE WRN SOUTH PLAINS. THE UA LOW IS STILL SOMEWHAT TIED TO
THE PARENT TROUGH THAT IS TRANSLATING EAST ACROSS SRN
CANADA...HOWEVER MODEL SOLUTIONS HINT AT IT PINCHING OFF LATER TODAY
AND THUS BECOME MORE CONCENTRIC. AS SUCH...THE SPEED OF THE UA LOW
COULD SLOW DOWN/BECOME WOBBLY AS THE CENTER GRADUALLY SHIFTS EAST TO
ACROSS NM TONIGHT...AND TO ACROSS THE CNTRL/SRN PLAINS BY EARLY
WEEKEND BEFORE FINALLY EXITING THE REGION SUNDAY AFTN/EVENING.

DESPITE BETTER MODEL CONSENSUS WRT TO THE GENERAL TRACK OF THE UA
LOW...THERE STILL REMAINS UNCERTAINTY WITH A FEW OF THE MESOSCALE
FEATURES. TOMORROW...THE GFS IS QUITE ROBUST IN SHIFTING THE DRYLINE
TO JUST EAST OF THE ROLLING PLAINS DURING THE AFTN HOURS...GIVEN ITS
DEPICTION OF A DEEPER NEARBY SFC TROUGH AND THUS BREEZY W-SW SFC
WINDS INVADING THE FA. THE NAM AND ECMWF ON THE OTHER-HAND EXHIBITS
THE DRYLINE TO SHARPEN UP AOA THE CAPROCK ESCARPMENT BY THE
AFTN...WITH A SLIGHTLY WEAKER DEPICTION OF THE SFC TROUGH...THEREBY
LEADING TO LIGHTER W-SW WIND SPEEDS. THIS COULD MEAN THE DIFFERENCE
BETWEEN CI OCCURRING ACROSS OUR ERN FRINGES OF THE CWA PER THE
GFS...OR OFF THE CAPROCK PER THE NAM AND ECMWF. FURTHERMORE...WITH
STEEPENED LAPSE RATES...PLENTIFUL MOISTURE /PWATS OF 1.00 INCH OR SO
ACROSS THE ROLLING PLAINS/...MUCAPE AOA 1000 J/KG AND 40-45 KTS OF 0-
6 KM BULK SHEAR...STORMS COULD BECOME STRONG TO SEVERE...MAKING THE
LOCATION OF THE DRYLINE ALL THE MORE IMPORTANT. SINCE THE GFS IS THE
OUTLIER...WILL LEAN TOWARDS THE OTHER SOLUTIONS AND THEREFORE
MAINTAIN HIGHEST POPS OFF THE CAPROCK TOMORROW. THE DRYLINE WILL
RETREAT CLOSE TO ON THE CAPROCK TOMORROW NIGHT/EARLY SATURDAY
MORNING...BEFORE GETTING SHUNTED EWRD TO EAST OF THE ROLLING PLAINS
BY SATURDAY AFTN...COURTESY OF A DEEPENING SFC TROUGH WHICH WILL
PROMOTE BREEZY W-SW SFC WINDS. THIS IS A SIGN OF THE UA LOW/S NWRD
JOG TOWARDS THE CNTRL PLAINS AND HENCE THE CWA GETTING DRYSLOTTED.
BEST CHANCES OF PRECIP WILL THEREFORE SHIFT NORTH AND EAST SATURDAY-
SUNDAY...WITH PERHAPS A BIT OF WRAP AROUND MOISTURE IMPINGING ON
THE NRN AND NERN ZONES SUNDAY...BUT THAT WILL BE DEPEND ON THE UA
LOW/S EXACT TRACK /THE GFS IS A TAD QUICKER/FARTHER NORTH WITH THE
UA LOW AND HENCE IS NOT SHOWING WRAP AROUND MOISTURE/.

A SLIGHTLY BREEZY COLD FRONT IS STILL PROGGED FOR SUNDAY BUT
FLEETING LARGE SCALE ASCENT COULD MAKE ADDITIONAL PRECIP HARD-
PRESSED TO DEVELOP. THEREAFTER...W-NW FLOW ALOFT WILL PREVAIL MONDAY-
TUESDAY...WHILST SFC WINDS VEER TO AN E-SE COMPONENT. THIS WILL
ENCOURAGE THE RETURN OF LOW LEVEL MOISTURE. AN EMBEDDED DISTURBANCE
AFFECTING THE REGION MONDAY NIGHT MAY BE THAT SYNOPTIC SPARK TO
INITIATE SHOWERS AND THUNDERSTORMS. FLOW ALOFT WILL BECOME MORE
ZONAL BY MID-WEEK...AND EMBEDDED IMPULSES WITHIN THIS FLOW ALOFT
COUPLED WITH THE RETURN OF THE DRYLINE MAY SET THE STAGE FOR MORE
OPPORTUNITIES FOR PRECIP.

CHANCES FOR RAINFALL AND THEREFORE INCREASED CLOUD COVER WILL KEEP
TEMPS AOA SEASONAL NORMS THROUGHOUT THE EXTENDED PERIOD.

&&

.PRELIMINARY POINT TEMPS/POPS...
FRIONA        74  43  68  41 /  30  30  10  10
TULIA         76  50  72  44 /  40  40  30  20
PLAINVIEW     76  52  72  45 /  50  40  30  10
LEVELLAND     76  50  72  44 /  30  40  20  10
LUBBOCK       78  53  74  46 /  50  40  20  20
DENVER CITY   76  49  72  44 /  20  30  10  10
BROWNFIELD    77  52  74  46 /  30  40  20  10
CHILDRESS     77  58  78  55 /  70  60  50  30
SPUR          78  56  76  53 /  60  60  40  20
ASPERMONT     80  60  77  56 /  60  60  50  40

&&

.LUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

99/99/55



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