FXUS64 KCRP 300318
AFDCRP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CORPUS CHRISTI TX
918 PM CST SUN NOV 29 2009
.DISCUSSION...COLD FRONT NOW ENTERING THE NORTHWEST PORTION
OF THE FORECAST AREA. TODAY SAW WIDESPREAD UPPER 70S AND LOWER
80S DESPITE CLOUD COVER THANKS TO A WELL MIXED ATMOSPHERE. WIND
GUSTS UP TO 30 MPH AT CRP. WINDS HAVE QUICKLY FALLEN OVER
ALL AREAS AND CONTINUE TO WEAKEN OVER THE OPEN WATERS.
CURRENTLY RADAR IS ECHO FREE BUT ISOLATED SHOWERS ARE JUST NORTH
OF VICTORIA. SHOWER DEVELOPMENT WILL BE SLOW TO OCCUR OVERNIGHT WHILE
THE SURFACE FRONT WILL CONTINUE SOUTHWARD AND REACH CRP ABOUT 09Z.
FRONT SHOULD ENHANCE OVER THE OPEN WATERS AS IT ENCOUNTERS MORE
INSTABILITY. AIR MASS LIFT WILL MOISTEN 850 TO 700 MB LAYERS
MONDAY MORNING AND PRECIPITABLALE WATERS ARE FORECAST TO RISE TO
AROUND 1.75 INCHES...AS SOUTHWEST FLOW ALOFT CONTINUES OVER THE
LOW LEVEL NORTH WIND. MAIN PLAYER IN OUR FORECAST IS THE LARGE
CLOSED UPPER LOW NOW OVER NORTHWEST MEXICO...TAKING AIM ON
BIG BEND. 850 MB EASTERLY FLOW WILL DEVELOP MONDAY AFTERNOON AND
INCREASE WHILE DEEPENING THROUGH 700 MB MONDAY NIGHT. THIS WILL
INCREASE RAINFALL. STRONG UPWARD MOTION AHEAD OF THE CLOSED UPPER
LOW WILL PRODUCE SURFACE CYCLOGENESIS OVER DEEP SOUTH TEXAS AND
ALSO INDUCE A COASTAL TROUGH LATER MONDAY NIGHT AND TUESDAY
MORNING. THIS WILL BE THE PERIOD OF HEAVIEST RAINFALL. 00Z NAM HAS
SHIFTED THIS FORCING FURTHER EAST COMPARED TO THE 18Z RUN BUT IS
STILL SIMILAR TO LAST NIGHTS 00Z RUN WHICH DEVELOPS LOW LEVEL
EASTERLIES OVER THE COASTAL BEND. GIVEN THE STRENGTH OF THE UPPER
TROUGH THERE WILL LIKELY BE LEE SIDE SURFACE LOW PRESSURE AND A
COASTAL LOW. RATHER INTENSE FGEN FORCING LATE MONDAY NIGHT AND
TUESDAY MORNING SUGGEST HEAVY RAINFALL BANDING OVER SOUTH
TEXAS...WHICH LIFTS INTO THE NORTHERN COASTAL BEND AND OFFSHORE BY
18Z TUESDAY WITH THE EJECTING 700 MB TROUGH.
WEAK LOW LEVEL WARM AIR ADVECTION PERSISTS INTO TUESDAY AFTERNOON
WHILE COLD AIR ADVECTION NEAR 500 MB OCCURS IN THE AFTERNOON AS THE
BASE OF THE CLOSED UPPER LOW SWINGS INTO SOUTHWEST TEXAS. THIS WILL
LEAD TO ANOTHER ROUND OF GOOD SYNOPTIC LIFT AND FURTHER DESTABILIZATION
FROM STEEPENING LAPSE RATES AND LIFTING. THUS ANOTHER ROUND OR LINE OF
HEAVY RAIN AND SOME THUNDERSTORMS WILL SWEEP ACROSS THE FORECAST
AREA TUESDAY AFTERNOON. THE COLD CORE IS PROGGED TO LIFT INTO CENTRAL
TEXAS TUESDAY NIGHT...DRAGGING A 850 TO 700 MB COLD FRONT ACROSS
THE REGION FOR THE LAST ROUND OF SHOWERS TUESDAY NIGHT FOLLOWED
BY PARTIAL CLEARING AND WINDY COLD AIR ADVECTION.
OVERALL RAINFALL POTENTIAL OF 1 TO 3 INCHES WITH AREAS OF 4 TO
6 INCHES FOR THE COASTAL BEND. PATTERN IS SIMILAR TO THE NOV 20TH
EVENT WHICH PLACES THE COASTAL BEND IN THE TARGET AREA BUT
IT IS ALSO EXPECTED THAT THE MAX RAINFALL COULD BE JUST OFFSHORE.
&&
.MARINE...WINDS HAVE DECREASED THROUGH THE DAY...ESPECIALLY
OFFSHORE. SEAS REMAIN NEAR 7 FEET AT BUOY 20. SCA WILL BE
NEEDED FOR WINDS ON MONDAY AND MAY ISSUE THIS NOW. WINDS STILL
PROGGED TO TAKE ON AN EASTERLY COMPONENT MONDAY NIGHT INTO
TUESDAY BEFORE SHIFTING ABRUPTLY BACK TO NORTHWEST TUESDAY
EVENING...AND BECOMING STRONG.
&&
.PREV DISCUSSION... /ISSUED 523 PM CST SUN NOV 29 2009/
DISCUSSION...PLEASE SEE THE AVIATION DISCUSSION BELOW FOR MORE
DETAILS.
AVIATION...A COLD FRONT WL PUSH INTO THE NORTHERN PORTIONS OF
SOUTH TX AROUND MIDNIGHT AND THEN QUICKLY SWEEP THROUGH THE
REMAINDER OF SOUTH TX THROUGH THE MORNING HOURS. MOSTLY VFR
CONDITIONS WL PREVAIL AHEAD OF THE FRONT EXCEPT ACROSS THE VCT
AREA WHERE SOME PATCHY MVFR CONDITIONS WL DEVELOP. MVFR CONDITIONS
WL DEVELOP QUCIKLY BEHIND THE FRONT AND LINGER THROUGH MUCH OF THE
DAY ON MONDAY AS COOL AIR UNDERCUTS WARM AIR ALOFT. RAIN WL
DEVELOP ALONG AND BEHIND THE FRONT. THE RAIN WL TEND TO TAPER OFF
ACROSS THE VCT AREA BY MON AFTN.
PREV DISCUSSION... /ISSUED 347 PM CST SUN NOV 29 2009/
SHORT TERM...WARM MOIST AIR ADVECTING INTO THE REGION
TODAY...WITH WARM TEMPERATURES AND GENERALLY CLOUDY SKIES. MAIN
WEATHER STORY OVER THE SHORT TERM IS A STRONG COLD FRONT CURRENTLY
PUSHING THROUGH WESTERN AND CENTRAL TEXAS. HAVE TRENDED TOWARD THE
SLOWER EUROPEAN MODEL OVER THE FASTER GFS...WITH THE FRONT PUSHING
THROUGH THE COASTAL BEND OVERNIGHT. EXPECT PRECIPITATION TO BEGIN
ALONG AND JUST AHEAD OF THE FRONT...WITH MOST OF THE PRECIPITATION
BEHIND THE FRONT.
MODELS KEEP SIGNIFICANT ENERGY WITH AN UPPER LOW TRACKING ACROSS
NORTHERN MEXICO THROUGH WEST TEXAS...TO THE POINT WHERE THE NAM
BRINGS COASTAL AREAS BACK INTO THE WARM SECTOR DURING THE DAY ON
MONDAY. WHILE THIS SEEMS OVERDONE...STRONG VERTICAL LIFT AND
COPIOUS MOISTURE WILL LEAD TO NOTICEABLE QPFS ACROSS COASTAL AREAS
MONDAY AND MONDAY NIGHT.
THE OTHER SIGNIFICANT EFFECT WILL BE A RAPID DROP IN TEMPERATURES.
HIGHS IN THE 80S TODAY WILL BE FOLLOWED UP BY HIGHS IN THE 50S
MONDAY AS STRONG NORTH WINDS BRING COLD AIR INTO SOUTH TEXAS.
WINDS WILL ALSO PICK UP OVER THE GULF AFTER THE FRONT PASSES...AND
SMALL CRAFT ADVISORIES WILL BE NECESSARY.
LONG TERM (TUESDAY THROUGH SATURDAY)...MAIN UPPER LOW WILL MOVE
ACROSS CEN TEXAS ON TUE-TUE NIGHT. LIKE THE SLOWER NAM/ECMWF WRT
THIS SYSTEMS MVMT. COMBINATION OF ISENTROPIC UPGLIDE AND LARGE SCALE
LIFT ASSOC W/ THE LOW WILL LEAD TO WIDESPREAD RAIN AND EMBEDDED
TSTMS POSSIBLE. DO NOT LIKE THE NAMS SUGGESTION THE FRONT WILL BACK
UP INTO THE COASTAL PLAINS ON TUE AND WILL KEEP THE BOUNDARY ALONG
THE COAST. THE RAIN WILL END FROM WEST TO EAST ON TUE NIGHT. GIVEN
THE SLOWER SOLNS WRT THE UPR LOW...LEANED TO HIGHER POPS FOR TUE
EVENING AS WELL W/ LIKELY POPS STILL IN THE ERN 3RD...BUT ONLY 10-20
POPS FAR WEST. RAIN IS EXPECTED TO END RAPIDLY IN THE EVENING W/
LITTLE PRECIP LEFT AFTR MIDNIGHT. STRONG CAA IS SHOWN FOR WED W/ H85
TEMPS DROPPING TO SINGLE DIGITS OR NEAR FREEZING. THEREFORE WENT W/
COOLER MOS DESPITE DECREASE IN CLOUDS ON WED AND LEANED COOL WED
NIGHT AS WELL AS A RE-ENFORCING HIGH ARRIVES. WILL SLOWLY MODIFY
BEYOND THAT HEADING TO THE END OF THE WEEK. MODELS ARE REALLY
STARTING TO SHOW PRECIP POTENTIAL W/ THE NEXT SYSTEM. FOR NOW HAVE
STAYED BELOW MOS POPS AND KEPT POPS IN SLT CHC CAT AND ONLY
MENTIONING IN ERN 2/3RDS OF THE REGION.
WITH TIDES INCREASING TO ASTRONOMICAL HIGHS THIS WEEK AND
DEVELOPMENT OF A COASTAL LOW...SOME COASTAL FLOODING WILL BE
POSSIBLE TUE AND WILL HAVE TO BEGIN STATEMENTS REGARDING THIS
POSSIBILITY TONIGHT OR MON. SMALL CRAFT ADVISORIES ALSO LIKELY
DURING THE FIRST FEW DAYS OF THE FORECAST PERIOD.
&&
.PRELIMINARY POINT TEMPS/POPS...
CORPUS CHRISTI 59 60 48 53 46 / 70 90 70 80 60
VICTORIA 53 55 43 50 44 / 80 80 70 80 70
LAREDO 55 57 45 52 45 / 70 80 60 70 10
ALICE 56 57 46 53 44 / 70 90 70 80 40
ROCKPORT 61 62 48 56 47 / 70 90 70 80 70
COTULLA 53 55 42 51 40 / 70 80 60 80 10
KINGSVILLE 59 60 49 55 44 / 70 90 70 80 50
NAVY CORPUS 62 62 51 57 47 / 70 90 70 80 60
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
AT/15...SHORT TERM
