993
FXUS63 KPAH 200447
AFDPAH
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PADUCAH KY
1147 PM CDT TUE MAR 19 2019
UPDATE
ISSUED AT 1147 PM CDT TUE MAR 19 2019
THE AVIATION SECTION HAS BEEN UPDATED FOR THE 06Z TAF ISSUANCE.
SHORT TERM
(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 325 PM CDT TUE MAR 19 2019
SURFACE HIGH PRESSURE WILL CONTINUE TO RETREAT TO THE EAST OF THE
WFO PAH FORECAST AREA THIS AFTERNOON AND THIS EVENING IN ADVANCE
OF SHORTWAVE/CLOSED LOW OVER CENTRAL AND EASTERN NEBRASKA. THE
SHORTWAVE WITH AN EMBEDDED LOW WILL SLOWLY ROTATE SOUTHEAST
THROUGH KANSAS AND MISSOURI TONIGHT AND WEDNESDAY, REACHING INTO
SOUTHEAST MISSOURI LATE AFTERNOON ON WEDNESDAY. A PRE-FRONTAL
TROUGH AXIS WILL DEVELOP DURING THE DAY, WORKING NORTHWEST TO
SOUTHEAST THROUGH THE AREA. THE AGEOSTROPHIC FORCING WILL LIKELY
GENERATE SOME PARCEL TRANSFER IN THE BOUNDARY LAYER, PRODUCING
SOME GUSTY SOUTHWEST WINDS FROM LATE MORNING AND THROUGH THE
AFTERNOON. IN THE ABSENCE OF DEEP LAYER MOISTURE, ANTICIPATE JUST
LIGHT RAIN AMOUNTS FROM DAYBREAK WEDNESDAY THROUGH EARLY WEDNESDAY
EVENING ACROSS THE WFO PAH FORECAST AREA. PRECIPITATION AMOUNTS
(QPF) SHOULD REMAIN BETWEEN A TRACE AND 0.20 OF AN INCH FOR
RAINFALL TOTALS FOR THE EVENT.
AS THE SHORTWAVE AND TROUGH EXIT THE WFO PAH FORECAST AREA BY
MIDNIGHT WEDNESDAY NIGHT, THE LEADING EDGE OF A SURFACE TO UPPER
LEVEL RIDGE WILL PUSH ACROSS THE AREA THURSDAY AND THURSDAY NIGHT.
WITH INCREASE SOUTHERLY FLOW TONIGHT INTO WEDNESDAY, ANTICIPATE
TEMPERATURES REMAINING SOME 5 TO 7 DEGREES ABOVE THIS MORNING'S
LOW TEMPERATURES, WITH HIGHS ON WEDNESDAY AT OR SLIGHTLY HIGHER
THAN TODAY, EVEN WITH CLOUD COVER AND INCREASING RAIN CHANCES.
TEMPERATURES ON THURSDAY AND THURSDAY NIGHT WILL DROP BACK ONLY A
FEW DEGREES AS THICKNESSES INCREASE IN THE WAKE OF THE DEPARTING
TROUGH, BALANCING WITH RADIATIONAL LOSS IN TEMPERATURES THURSDAY
NIGHT.
LONG TERM
(FRIDAY THROUGH TUESDAY)
ISSUED AT 325 PM CDT TUE MAR 19 2019
RIDGING WILL CONTINUE TO DOMINATE THE WFO PAH FORECAST AREA
THROUGH SATURDAY. PREVIOUS (FROM THIS PAST WEEKEND) AND CURRENT
MEDIUM RANGE NUMERICAL MODEL TRENDS HAVE BEEN SHOWING THAT THE
RIDGE WOULD REMAIN DOMINATE THROUGH SATURDAY, MOVING EAST SATURDAY
NIGHT. THE NORTHWARD MOISTURE TRAJECTORY FROM THE WESTERN GULF OF
MEXICO CONTINUES TO REMAIN PERSISTENT FROM RUN TO RUN IN THE
MEDIUM RANGE MODEL SUITE, FOCUSING MOST OF THE RAIN IN A
NORTH/SOUTH CORRIDOR, BALANCES BY THERMAL INSTABILITY DUE TO THE
MOISTURE FROM THE SOUTH AND THE DYNAMIC INSTABILITY ASSOCIATED
WITH THE NEXT SERIES OF SHORTWAVES AMPLIFYING THE QUASI-ZONAL FLOW
OVER THE NORTHWEST QUARTER OF THE NATION ON SUNDAY INTO MONDAY.
THERE IS HIGH CONFIDENCE OF THE RAIN CHANCES ASSOCIATED WITH THE
SYSTEM MOVING ACROSS SUNDAY AND MONDAY, BUT THE MECHANISM OF LIFT
IS SOMEWHAT UNCERTAIN, DEPENDING ON THE MODEL GUIDANCE YOU PREFER.
WITH THAT IN MIND, HAVE LOW FORECAST CONFIDENCE ON TUESDAY AND
TUESDAY NIGHT ON THE COVERAGE AND TYPE OF PRECIPITATION. THE GFS
DETERMINISTIC SOLUTION FAVORS A MORE DISTINCT AND PROGRESSIVE
SHORT WAVELENGTH TROUGH-RIDGE-TROUGH PATTERN EARLY NEXT WEEK,
WHILE THE ECMWF DEPICTS AN EXITING EASTERN U.S. TROUGH AND AND
APPROACHING SPLIT FLOW WITH A NORTHERN RIDGE/SOUTHERN TROUGH
ENVELOPING THE WFO PAH FORECAST AREA ON TUESDAY.
THE INSTABILITY FORECAST (FOR THUNDERSTORM MENTION) MAY CHANGE
MARKEDLY SUNDAY INTO MONDAY FOR THE NEXT FEW FORECAST CYCLES UNTIL
THE ORIENTATION AND PLACEMENT OF SHORTWAVE TRANSVERSING ACROSS THE
AREA BECOMES MORE WELL DEFINED. GIVEN THE POTENTIAL MESOSCALE
NATURE OF THE SHORTWAVE, ANY DEFINED THUNDERSTORM COVERAGE MAY NOT
COME INTO MORE DISTINCT VIEW UNTIL THE FRIDAY FORECAST PACKAGE.
FROM A SENSIBLE WEATHER PERSPECTIVE, THERE IS HIGH FORECAST
CONFIDENCE FOR RAIN SUNDAY INTO MONDAY AND LESS CONFIDENCE TUESDAY
AND BEYOND.
AVIATION
ISSUED AT 1147 PM CDT TUE MAR 19 2019
COMPLEX UPPER PATTERN THROUGH THE PERIOD, WITH A PAIR OF MINOR
IMPULSES BRINGING SOME LIGHT SHOWERS TO THE REGION THROUGH THE
DAY, AND THEN A LARGER-SCALE UPPER TROUGH BRINGING MORE PROLONGED
RAINS TO SOUTHWEST INDIANA AND WEST KENTUCKY THROUGH THE EVENING.
THERE IS NO WELL-DEFINED SURFACE BOUNDARY, SO LEANED TOWARD THE
OPTIMISTIC SIDE OF GUIDANCE AND KEPT CONDITIONS IN THE UPPER HALF
OF MVFR AT ALL SITES IN THE RAIN. SOME GUIDANCE SUPPORTS IFR
CEILINGS IN THE RAIN IN THE LATE AFTERNOON AND EVENING, SO
ADJUSTMENTS LOWER MAY BE NECESSARY WITH SUBSEQUENT FORECASTS.
PAH WATCHES/WARNINGS/ADVISORIES
IL...NONE.
MO...NONE.
IN...NONE.
KY...NONE.
UPDATE...DRS
SHORT TERM...SMITH
LONG TERM...SMITH
AVIATION...DRS
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page