Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
402 PM EDT Wed Sep 15 2021

Valid 00Z Thu Sep 16 2021 - 00Z Sat Sep 18 2021

...Tropical Depression Nicholas is forecast to slowly dissipate with a
Moderate Risk of excessive rainfall over parts of the Central Gulf Coast
through Thursday morning...

...There is a Slight Risk of excessive rainfall over parts of the
Northeast to parts of the Tennessee Valley through Thursday morning...

...There is a Slight Risk of severe thunderstorms over parts Northeast and
northern Mid-Atlantic through Thursday morning...

...There is an Elevated Risk of fire weather over parts of the Northern
High Plains/ Northern Rockies into the Great Basin...

The Tropical Depression Nicholas will slowly dissipate over Louisiana by
Friday evening while producing showers and thunderstorms.  The system will
produce heavy rain over parts of the Central Gulf Coast through Friday. 
Therefore, the WPC has issued a Moderate Risk of excessive rainfall with
these thunderstorms. The associated heavy rain will create numerous areas
of flash flooding. Furthermore, many streams may flood, potentially
affecting larger rivers through Thursday morning. The excessive rainfall
threat will weaken slightly to a Slight Risk of excessive rainfall over
parts of the Central Gulf Coast on Thursday into Friday.

Meanwhile, a front extending from the Northeast southwestward to the
Middle/Lower Mississippi Valley will become quasi-stationary while the
western end dissipates by Thursday afternoon.  The eastern part of the
boundary will weaken on Friday until dissipating by Friday evening. 
Moisture pooling along the front will aid in producing showers and
thunderstorms along and ahead of the boundary, and some of the storms will
become severe. Therefore, the SPC has issued a Slight Risk of severe
thunderstorms over parts of the Northeast and northern Mid-Atlantic
through Thursday morning.  The hazards associated with these thunderstorms
are frequent lightning, severe thunderstorm wind gusts, hail, and a few
tornadoes.  Furthermore, the showers and thunderstorms will produce heavy
rain.  Therefore, the WPC has issued a Slight Risk of excessive rainfall
with these thunderstorms. The associated heavy rain will create mainly
localized areas of flash flooding, with urban areas, roads, and small
streams the most vulnerable through Thursday morning.  The severe
thunderstorm threat weakens along with the excessive rainfall threat on
Thursday.  Showers and thunderstorms will continue over parts of the
Northeast/Mid-Atlantic through Friday evening.

Meanwhile, a front extending from the Northern High Plains southwestward
to the Great Basin will move eastward to the Great Lakes by Friday
evening.  Showers and thunderstorms will develop along and ahead of the
boundary on Thursday afternoon into Thursday evening, with some of the
storms becoming severe. Therefore, the SPC has issued a Slight Risk of
severe thunderstorms over parts of the Upper Mississippi Valley into the
Northern Plains on Thursday into Friday morning.  The hazards associated
with these thunderstorms are frequent lightning, severe thunderstorm wind
gusts, hail, and a few tornadoes.  Another front will begin to move
onshore over the Pacific Northwest on Friday bring moderate to heavy rain
over parts of the Pacific Northwest starting on Friday.

Furthermore, temperatures will be 10 to 15 degrees above average over
parts of the Northern High Plains and Northern Rockies.  A front moving
over the area will aid in producing gusty winds and with dry conditions in
place, there is an Elevated Risk of fire weather over parts of the
Northern High Plains/Northern Rockies into the Great Basin through
Thursday morning. Therefore, Red Flag Warnings are issued over the area
due to high temperatures, low moisture content, and gusty winds.   

Ziegenfelder

Graphics are available at www.wpc.ncep.noaa.gov/basicwx/basicwx ndfd.php