Skip Navigation Links weather.gov 
NOAA logo - Click to go to the NOAA homepage National Weather Service   NWS logo - Click to go to the NWS homepage
The Weather Prediction Center

 
 

 

Follow the Weather Prediction Center on Facebook Follow the Weather Prediction Center on Twitter
NCEP Quarterly Newsletter
WPC Home
Analyses and Forecasts
   National High & Low
   WPC Discussions
   Surface Analysis
   Days ½-2½ CONUS
   Days 3-7 CONUS
   Days 4-8 Alaska
   QPF
   PQPF
   Flood Outlook
   Winter Weather
   Storm Summaries
   Heat Index
   Tropical Products
   Daily Weather Map
   GIS Products
Current Watches/
Warnings

Satellite and Radar Imagery
  GOES-East Satellite
  GOES-West Satellite
  National Radar
Product Archive
WPC Verification
   QPF
   Medium Range
   Model Diagnostics
   Event Reviews
   Winter Weather
International Desks
Development and Training
   Development
WPC Overview
   About the WPC
   Staff
   WPC History
   Other Sites
   FAQs
Meteorological Calculators
Contact Us
   About Our Site
 
USA.gov is the U.S. Government's official web portal to all federal, state, and local government web resources and services.
 
 
< Day 1 Outlook Day 3 Outlook >
 
WPC Day 2 Excessive Rainfall Outlook
Risk of 1 to 6 hour rainfall exceeding flash flood guidance at a point
 
Updated: 1950 UTC Fri Nov 27, 2020
Valid: 12 UTC Nov 28, 2020 - 12 UTC Nov 29, 2020
 
Day 2 Excessive Rainfall Forecast
 
Forecast Discussion
 
Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
250 PM EST Fri Nov 27 2020
 
Day 2
Valid 12Z Sat Nov 28 2020 - 12Z Sun Nov 29 2020 

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF 
THE WESTERN GULF COAST...

...West/Central Gulf Coast...

At the start of the forecast period (Sat-28.12z), ongoing activity 
from today into tonight will be lingering in the vicinity of the 
Western Gulf coast, along a well defined surface frontal zone.  
Strong southerly flow (West Gulf LLJ) along  responding to the 
approach of strong closed low height falls out of the Southern 
High Plains, but become increasingly weaker but still confluent 
along the frontal boundary toward the LA coast.  The LLJ will be 
pumping deep tropical moisture (1.75 to near 2" Total PWats) 
providing even 1000-1250 J/kg of instability at 12z within the 
axis of the LLJ toward the boundary.  As such ongoing activity may 
back-build and regenerate across the Northwest Gulf of Mexico and 
adjacent coastal SE Texas.  Uncertainty remains in the precise 
location of the frontal zone due to strength of outflow boundary 
today, yet the response for increased convection will pose another 
round as the surface wave develops and deepens throughout the day 
into Sunday morning, as it nears SW LA.  Hi-Res CAMs and global 
guidance remain trending a bit more off-shore with the most 
vigorous/surface rooted convection, however, there is ample signal 
particularly from the slower guidance (12z ECMWF) for stronger 
more northward shift and increased rainfall rates and totals 
potentially over areas affected by today's rainfall.  As such, 
very little has changed with the placement of the Slight Risk of 
Excessive Rainfall covering much of Southeast Texas into 
Southwest/South-Central LA to account for the continued model 
spread; although highest confidence/greater risk appears to be 
within the coastal counties in TX/parishes in LA.

Gallina/Campbell
 
Day 2 threat area: www.wpc.ncep.noaa.gov/qpf/98epoints.txt
 

NOAA/ National Weather Service
National Centers for Environmental Prediction
Weather Prediction Center
5830 University Research Court
College Park, Maryland 20740
Weather Prediction Center Web Team
Disclaimer
Credits
Glossary
Privacy Policy
About Us
Career Opportunities