248
FXUS64 KLUB 240519
AFDLUB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LUBBOCK TX
1219 AM CDT FRI SEP 24 2021
AVIATION
VFR CONDITIONS WILL PREVAIL.
PREV DISCUSSION... /ISSUED 227 PM CDT THU SEP 23 2021/
SHORT TERM...
THE AXIS OF A DE-AMPLIFYING MID/UPPER-LEVEL RIDGE CONTINUES TO
CENTER OVER THE CWA AS A WEAK SHORTWAVE TROUGH PIVOTS OVER THE
DESERT SOUTHWEST THIS AFTERNOON. CYCLOGENESIS OF A BROAD LEE LOW HAS
COMMENCED ACROSS THE RATON MESA AS PER REGIONAL METAR DATA, WHICH
HAS RESULTED IN A DIFFUSE PRESSURE GRADIENT (EVIDENT ON WEST TEXAS
MESONET DATA) ACROSS THE REGION. VERTICAL MIXING HEIGHTS SHOULD
EXTEND INTO THE MID-LEVELS BY PEAK HEATING, SCOURING OUT MOISTURE
WITH RELATIVE HUMIDITY FALLING INTO THE UPPER TEENS AS DRY-BULBS
WARM TO MIDDLE 80S THIS AFTERNOON. BREEZY CONDITIONS WILL CONTINUE
OVERNIGHT AS THE NOCTURNAL LOW-LEVEL JET RE-INTENSIFIES TO 30-35 KT
IN RESPONSE TO A SHORTWAVE TROUGH ROTATING OVER THE CENTRAL GREAT
PLAINS, WHICH SHOULD RESULT IN A MILDER NIGHT COMPARED TO THE LAST
FEW WITH TEMPERATURES FALLING INTO THE LOWER 50S AREA-WIDE. A FEW
AREAS ACROSS THE NORTHWESTERN SOUTH PLAINS MAY OBSERVE TEMPERATURES
IN THE UPPER 40S SHORTLY BEFORE SUNRISE. FRIDAY WILL BE A "RINSE AND
REPEAT" WITH SIMILAR CONDITIONS AS TODAY GIVEN PERSISTENT LOW-LEVEL
WAA, THOUGH BOUNDARY-LAYER MIXING SHOULD BE MORE VIGOROUS WEST OF
THE EDGE OF THE CAPROCK ESCARPMENT AS THETA-E ADVECTION BECOMES
NEARLY CONSTANT WITH HEIGHT THROUGH 700-650 MB IN THE AFTERNOON.
SINCAVAGE
LONG TERM...
SOUTHERLY BREEZES, COOL NIGHTS AND WARM AND DRY AFTERNOONS WILL
PREVAIL THROUGH THE WEEKEND AS WEST TEXAS REMAINS POSITIONED BENEATH
SHORTWAVE RIDGING. THE ONLY CAVEAT IS THAT A COLD FRONT ASSOCIATED
WITH BROAD TROUGH/LOW OVER EASTERN CANADA INTO THE GREAT LAKES MAY
GRAZE THE NORTHERN/NORTHEAST ZONES EARLY SATURDAY. EVEN IF THE FRONT
DOES MAKE IT INTO THE CWA, IT SHOULD QUICKLY RETREAT WITH MINIMAL
IMPACTS LOCALLY.
THE PATTERN WILL TAKE A MORE INTERESTING TURN NEXT WEEK AS AN UPPER
LOW THAT WILL HANG OUT OVER THE DESERT SOUTHWEST THROUGH THE WEEKEND
EJECTS SLOWLY EASTWARD AHEAD OF A LARGE TROUGH ACROSS THE EASTERN
PACIFIC. INITIALLY, LOW LEVEL MOISTURE WILL BE RATHER MEAGER, BUT
SHOULD IMPROVE BY TUESDAY AS THE GULF OF MEXICO BEGINS TO OPEN BACK
UP. EVEN SO, LIFT AND INCREASING MID-UPPER LEVEL MOISTURE FROM THE
APPROACHING SYSTEM MAY PROVIDE SLIM SHOWER/STORM CHANCES ON MONDAY,
WITH BETTER CHANCES BY TUESDAY. THERE REMAINS PLENTY OF DETAILS
TO BE RESOLVED THAT WILL DICTATE EXACTLY WHERE AND WHEN THE BEST
RAIN CHANCES WILL BE, BUT THE ENTIRE REGION WILL HAVE A CHANCE OF
SEEING PRECIPITATION NEXT WEEK. THE INITIAL UPPER LOW IS PROGGED
TO OPEN AND LIFT NORTHWARD AROUND THE MIDDLE OF THE WEEK, BUT
SHOULD QUICKLY BE REPLACED BY ADDITIONAL TROUGHING THROUGH LATE
WEEK. THIS WILL KEEP RAIN CHANCES GOING THROUGH LATE WEEK, AFTER
PERHAPS A RELATIVE LULL BETWEEN THE TWO WAVES. GIVEN THE PATTERN,
AND IMPROVING DEEP-LAYER MOISTURE, WE HAVE ACCEPTED THE NBM POPS
WHICH NOW SHOW SLIGHT CHANCE TO SOLID CHANCE POPS OVER A GOOD
CHUNK OF THE CWA FROM MONDAY THROUGH FRIDAY. RATHER LIMITED
INSTABILITY AND WIND SHEAR SHOULD TEND TO HINDER STORM
ORGANIZATION AND INTENSITY, THOUGH A ROGUE STRONG STORM ISN'T OUT
OF THE QUESTION. LOCALLY HEAVY RAINFALL MAY BE A BIGGER THREAT, AT
LEAST ONCE THE BETTER LOW-LEVEL MOISTURE ARRIVES. OTHERWISE,
TEMPERATURES WILL TREND BACK TOWARD AND PERHAPS EVEN BELOW AVERAGE
AS WE PROGRESS THROUGH NEXT WEEK.
FIRE WEATHER...
NO CHANGES MADE TO THIS MORNING'S FIRE WEATHER ASSESSMENT. BREEZY
SOUTH WINDS WILL CONTINUE FOR THE REST OF THE AFTERNOON, AND THE
FIRE DANGER STATEMENT REMAINS IN EFFECT FOR THE NORTHEASTERN ROLLING
PLAINS THROUGH 24/00Z (7 PM CDT) THIS EVENING. MINIMUM RH VALUES
WILL FALL TO NEAR 15 PERCENT DUE TO VERY WARM TEMPERATURES AND SOUTH
WINDS BETWEEN 15-20 MPH. BREEZY CONDITIONS WILL PERSIST OVERNIGHT
WITH RH RECOVERING ABOVE 50 PERCENT. SIMILAR CONDITIONS ARE EXPECTED
TO DEVELOP TOMORROW AFTERNOON, AND NO FIRE HEADLINES ARE WARRANTED
AT THIS TIME.
SINCAVAGE
LUB WATCHES/WARNINGS/ADVISORIES
NONE.
51/99/99
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