282 
FXUS64 KFWD 200901
AFDFWD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FORT WORTH TX
401 AM CDT TUE OCT 20 2015

.DISCUSSION...
WATER VAPOR LOOP SHOWS THE LARGE UPPER LEVEL TROUGH ACROSS THE
WESTERN U.S. HAS MADE SLOW PROGRESS EASTWARD DURING THE LAST DAY.
HEIGHT FALLS ARE NOW OVERSPREADING THE LEE OF THE SOUTHERN ROCKIES
WHICH IS RESULTING IN AN EROSION OF THE WESTERN PORTION OF THE
SPRAWLING SURFACE HIGH THAT HELPED BRING US THE PLEASANT BUT DRY
WEATHER DURING THE LAST FEW DAYS.

SOUTHERLY WINDS WILL CONTINUE TO INCREASE TODAY...ESPECIALLY
ABOVE THE SURFACE WHICH WILL BEGIN TO TRANSPORT GULF MOISTURE INTO
THE AREA. THIS SHOULD BRING SOME LOW CLOUDS INTO THE SOUTHEASTERN
PARTS OF THE AREA THIS MORNING...BUT GENERALLY MOSTLY SUNNY SKIES
ARE EXPECTED EVERYWHERE THIS AFTERNOON. HIGH TEMPS WILL CONTINUE
TO RUN A FEW DEGREES ABOVE NORMAL FOR THE NEXT 3 DAYS WITH VALUES
FAIRLY SIMILAR TO YESTERDAY'S READINGS. THE GOOD NEWS IS THAT THE
HIGHER HUMIDITY WILL HELP TO MITIGATE THE WILDFIRE THREAT...BUT
STILL RH WILL DROP BELOW 30 PERCENT ACROSS THE FAR WESTERN ZONES
THIS AFTERNOON. MOISTURE WILL CONTINUE TO INCREASE TONIGHT...SO
TODAY WILL BE THE LAST DAY OF FIRE WEATHER CONCERNS AS MIN RH ON
WEDNESDAY WILL STAY ABOVE 50 PERCENT AS DEWPOINTS RISE INTO THE
60S. WITH THE RISING DEWPOINTS WILL COME MORE LATE NIGHT AND
MORNING CLOUD COVER AND LOW TEMPERATURES WILL BE IN THE 60S.

MAJOR WEATHER CHANGES ARE FORECAST TO OCCUR LATER THIS WEEK AS THE
AFOREMENTIONED UPPER TROUGH EJECTS OUT INTO THE PLAINS FRIDAY AND
IS QUICKLY SUCCEEDED BY ANOTHER STRONG SHORTWAVE TROUGH THAT MOVES
THROUGH ON SATURDAY. THIS IS A VERY FAVORABLE UPPER LEVEL PATTERN
FOR A PROLONGED RAIN EVENT IN NORTH TEXAS AS THE TRACK OF THE
FIRST SYSTEM WILL KEEP CONVECTION FROM SCOURING OUT MOISTURE AND
RESULT IN A SECOND ROUND OF RAINS ON SATURDAY. IN ADDITION DEEP
SOUTHERLY FLOW IN THE LOWEST 8000FT WILL TAP INTO RICH TROPICAL
MOISTURE FROM THE SOUTHERN BAY OF CAMPECHE RESULTING IN
PRECIPITABLE WATER SURGING ABOVE 2 INCHES...WHICH IS AN
ANOMALOUSLY HIGH VALUE FOR OCTOBER AT 2 STANDARD DEVIATIONS ABOVE
NORMAL. THE BONUS INGREDIENT LOOKS TO BE SOON TO BE NAMED TROPICAL
CYCLONE PATRICIA IN THE EASTERN PACIFIC OCEAN...WHICH MODELS
CONTINUE TO TURN NORTH INTO MEXICO FRIDAY NIGHT AND SATURDAY. IN
ADDITION TO PROVIDING PACIFIC MOISTURE ALOFT TO THE REGION...THE
TROPICAL CYCLONE WILL PRODUCE A STRONGER UPPER LEVEL ANTICYCLONE
TO OUR SOUTH...WHICH WILL HELP TO INCREASE THE DIVERGENCE ALOFT
OVER TEXAS. POPS HAVE BEEN INCREASED FROM THURSDAY NIGHT INTO
SATURDAY AS CONFIDENCE IN WIDESPREAD RAIN CONTINUES TO RISE.

FOR THE SPECIFICS IN THE CONVECTIVE FORECAST...WILL BRING SOME
LOW POPS FOR SHOWERS INTO MAINLY THE WESTERN ZONES ON WEDNESDAY
AS THIS IS WHERE THE BEST AXIS OF MOISTURE SHOULD RESIDE. AS THE
FIRST UPPER TROUGH APPROACHES THURSDAY...CONVECTION WILL BECOME
MORE SCATTERED OVER THE AREA ON THURSDAY AFTERNOON. THERE SHOULD
BE ENOUGH INSTABILITY TO AT LEAST BE CONCERNED ABOUT A THREAT FOR
STRONG OR POSSIBLY MARGINALLY SEVERE STORMS THURSDAY AFTERNOON AND
EVENING GIVEN THE WELL ORGANIZED SHEAR PROFILES. THIS INSTABILITY
IS DEFINITELY ON THE LOW SIDE FOR A SEVERE WEATHER POTENTIAL...BUT
WILL CONTINUE TO MONITOR. ON THURSDAY NIGHT THE MAIN CONVECTIVE
BAND SHOULD DEVELOP ACROSS WEST AND NORTHWEST TEXAS AND SLOWLY
TRACK EAST INTO AND ACROSS THE AREA ON FRIDAY. TEMPERATURES FRIDAY
WILL BE HELD DOWN IN THE 70S DUE TO WIDESPREAD RAINFALL...DESPITE
CONTINUING SOUTHERLY WINDS. THERE SHOULD BE A LULL IN THE RAIN
ACTIVITY FRIDAY NIGHT...BUT CONVECTION SHOULD GIN UP AGAIN OVER
THE AREA BY SATURDAY MORNING AS LIFT FROM THE SECOND SHORTWAVE
BEGINS TO IMPINGE ON THE AREA. THIS BAND OF CONVECTION WILL TRACK
EASTWARD DURING THE DAY SATURDAY. SURFACE WINDS TURN TO THE NORTH
LATE SATURDAY AS A NON-TROPICAL SURFACE LOW DEVELOPS ALONG THE
TEXAS COAST OUT OF THE UPPER LEVEL REMNANTS OF PATRICIA. DUE TO
WIDESPREAD CONVECTION AND COOL TEMPERATURES IN THE 70S...INSTABILITY
LOOKS TOO MINIMAL FOR A SEVERE WEATHER THREAT FRIDAY AND SATURDAY.
NORTHERLY WINDS WILL RESULT IN LOW LEVEL COLD/DRY ADVECTION
SATURDAY NIGHT AND SUNDAY...BUT WRAP AROUND MOISTURE/LIFT BEHIND A
DEEPENING CLOSED UPPER LOW MAY KEEP SHOWERS IN THE REGION SUNDAY.

OCTOBER IS THIS REGION'S 2ND WETTEST MONTH...AND IT IS USUALLY
BECAUSE OF SETUPS LIKE THESE. THE INTERACTION OF THE UPPER LEVEL
SYNOPTIC WESTERLIES PORTENDING THE ARRIVAL OF WINTER AND HIGH
AMOUNTS OF MOISTURE LEFT OVER FROM SUMMERTIME IN THE TROPICS CAN
COMBINE TO PRODUCE EXCESSIVE RAINFALL AMOUNTS. INTERESTINGLY
ENOUGH...ALTHOUGH CLIMATOLOGY SHOWS A BUMP IN PRECIPITATION IN
THE AUTUMN...AN INCREASE IN FLASH FLOOD EVENT FREQUENCY IS MORE
MUTED. THIS IS LIKELY BECAUSE THE GROUND IS USUALLY DRIED OUT
FROM THE HOT AND DRY SUMMER MONTHS AND VEGETATION HAS YET TO
BECOME DORMANT. THUS WHILE THE POTENTIAL FOR FLASH FLOODING DOES
EXIST THURSDAY NIGHT INTO SATURDAY...CLIMATOLOGY AND OUR RECENT
DROUGHT CONDITIONS ARE SUGGESTING TO HOLD OFF ON A FLASH FLOOD
WATCH UNTIL WE AT LEAST GET IN RANGE OF SOME HIGH-RESOLUTION
GUIDANCE THAT CAN PINPOINT RAIN AMOUNTS AND THREAT AREAS WITH SOME
CONSISTENCY. FURTHERMORE...WHILE WE ARE FORECASTING 2-3 INCHES
AREAWIDE WITH THIS EVENT...THIS RAIN MAY FALL OVER A LONG ENOUGH
TIME RANGE TO KEEP THE FLOODING THREAT MANAGEABLE.

DRIER AND SEASONABLE CONDITIONS ARE EXPECTED EARLY NEXT WEEK AS
THIS TROUGH MOVES OFF TO THE EAST AND NORTHERLY SURFACE FLOW
PREVAILS.

TR.92

&&

.AVIATION...
/ISSUED 1129 PM CDT MON OCT 19 2015/
CONCERNS...POSSIBLE MVFR CONDITIONS AT WACO AROUND/JUST AFTER
DAYBREAK TUESDAY /13Z/.

AS AN UPPER LEVEL TROUGH THAT IS MOVING INTO THE SOUTHWESTERN
UNITED STATES MOVES EAST...A WEAK LOW LEVEL JET IS DEVELOPING
ACROSS TEXAS. THIS LOW LEVEL JET SHOULD HELP BRING SOME GULF
MOISTURE NORTH INTO CENTRAL TEXAS BEFORE DAYBREAK TUESDAY. THUS
HAVE INDICATED A FEW HOURS OF MVFR CEILING IN THE WACO AREA FROM
13Z THROUGH 16Z TUESDAY. OTHERWISE VFR CONDITIONS ARE EXPECTED
THROUGH 06Z WEDNESDAY WITH SOUTHEAST WIND 10 TO 15 KNOTS...WITH
SOME GUSTS OVER 20 KNOTS LIKELY TUESDAY AFTERNOON. MVFR CEILINGS
ARE EXPECTED TO SPREAD NORTHWARD AGAIN TUESDAY NIGHT...MOVING INTO
WACO AROUND 06Z WEDNESDAY AND INTO THE METROPLEX AFTER 09Z
WEDNESDAY.

58


&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  83  67  83  67  85 /   0   0  10  10  20 
WACO, TX              84  66  84  66  85 /   5  10  20  20  30 
PARIS, TX             81  61  83  61  83 /   0   0  10  10  10 
DENTON, TX            82  64  82  64  83 /   0   0  10  10  20 
MCKINNEY, TX          82  64  83  63  84 /   0   0  10  10  20 
DALLAS, TX            83  67  83  67  85 /   0   0  10  10  20 
TERRELL, TX           82  63  84  64  85 /   0   0  10  10  20 
CORSICANA, TX         84  66  85  66  86 /   5   5  10  10  20 
TEMPLE, TX            83  65  83  65  82 /   5  10  30  20  30 
MINERAL WELLS, TX     84  63  81  63  80 /   0   5  20  20  40 

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$