WPC Excessive Rainfall Outlook Day 1
Day 1 Outlook Day 2 Outlook Day 3 Outlook

Images courtesy of the NWS Weather Prediction Center
 Excessive Rainfall Forecast Discussion
Excessive Rainfall Discussion

433
FOUS30 KWBC 212102
QPFERD

EXCESSIVE RAINFALL DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
501 PM EDT THU SEP 21 2017

...VALID 2101Z THU SEP 21 2017 - 12Z FRI SEP 22 2017...
...REFERENCE AWIPS GRAPHIC UNDER...DAY 1 EXCESSIVE RAINFALL...


MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
55 ESE U24 15 SE SGU 50 NW SGU 60 NE TPH 50 SE EKO 30 NNW ENV
65 S 77M 15 ESE SLC 55 ESE U24.

MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
10 WNW HAI MKG 20 SW CAD 25 ENE HTL 15 ENE P58 10 N PHN ADG
10 WNW HAI.

MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 E BJI BFW ARV 10 W RRL 30 ENE EAU 10 WSW OEO 15 WSW DXX
35 SSW ABR 30 SW FAR 20 E BJI.

MARGINAL RISK OF RAINFALL EXCEEDING FFG TO THE RIGHT OF A LINE FROM
20 SE LBX 20 NNW KBQX 30 E KRP 10 SSE NGP 50 N ALI BAZ
15 WNW 3T5 15 NW LBX 20 ESE LBX 20 SE LBX.


GREAT BASIN
~~~~~~~~~~~
A LARGE TROUGH WILL SWING FROM POSITIVE TO NEAR NEUTRAL TILT,
PRODUCING COOLING ALOFT NEAR ITS BASE ACROSS EASTERN NEVADA AND
MUCH OF UTAH. THE PATTERN WOULD BE FAVORABLE FOR THUNDERSTORMS
OVER SOUTHERN NEVADA AND MUCH OF UTAH THIS AFTERNOON...EXCEPT FOR
VERY DRY LOW LEVEL AIR WHICH WILL LIMIT INSTABILITY AND THE
EFFECTIVENESS OF ANY STORMS THAT MANAGE TO FORM. THE HI-RES MODELS
INDICATE LITTLE...IF ANY...CAPE. THERE IS SOME INDICATION OF
DEEPER MOISTURE AND HIGHER SURFACE DEW POINTS...IN THE MIDDLE
40S...ADVECTING UP THROUGH SOUTHEAST NEVADA INTO SOUTHERN UTAH BY
AFTERNOON. STILL...FORECAST SOUNDINGS INDICATE EVEN THIS WOULD BE
INSUFFICIENT TO PRODUCE MUCH INSTABILITY. GIVEN AN INHERITED
MARGINAL RISK AREA...WE CHOSE TO KEEP IT IN PLACE ON THE OFF
CHANCE THAT DEEP SYNOPTIC ASCENT CAN COMPENSATE FOR POOR LOW LEVEL
MOISTURE TO PRODUCE AN ISOLATED HEAVY RAIN THREAT OVER SOME OF THE
SLOT CANYON / FLASH-FLOOD PRONE TERRAIN IN THIS REGION.


MIDDLE TX COAST
~~~~~~~~~~~~~~~
A HIGH PRECIPITABLE WATER REGIME COMBINED WITH CONVERGENT 850 HPA
INFLOW OF 15 KTS HAS BEEN CAUSING THUNDERSTORM PRODUCTION WITHIN
EASTERN TX.  DIVERGENCE ALOFT IS BEING SPONSORED BY A SHORTWAVE
MOVING IN FROM WESTERN TX, NOTICEABLE IN RECENT WATER VAPOR
IMAGERY.  THE MEAN 850-400 HPA FLOW IS CLOSE TO 5 KTS, SO THE
STORMS HAVE BEEN EFFICIENT.  EFFECTIVE BULK SHEAR IN THE REGION IS

Record Report from: NOAA-NWS
Script developed by: El Dorado Weather & modified by: SE Lincoln Weather