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. && $$