Storm Prediction Center Forecast


RSS Mesoscale Discussions from Storm Prediction Center

SPC - No watches are valid as of Thu Oct 18 06:41:02 UTC 2018

No watches are valid as of Thu Oct 18 06:41:02 UTC 2018.


SPC - No MDs are in effect as of Thu Oct 18 06:41:02 UTC 2018

No Mesoscale Discussions are in effect as of Thu Oct 18 06:41:02 UTC 2018.


SPC Oct 18, 2018 0600 UTC Day 1 Convective Outlook

SPC 1200Z Day 1 Outlook
      
Day 1 Outlook Image
Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
1258 AM CDT Thu Oct 18 2018

Valid 181200Z - 191200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Isolated thunderstorms are possible across parts of Texas and the
Florida Peninsula, and parts of the Intermountain West through
tonight, but severe storms are not anticipated.

...Discussion...
Evolution of the upper pattern is forecast today, as an upper trough
crossing eastern Canada and New England advances/moves offshore.  In
the wake of this feature, flow will relax/become more westerly
across the Midwest.

Meanwhile in the west, the weakening cut-off low over the
Intermountain region will gradually begin to eject eastward, as it
gets kicked by a trough digging southeast across the Canadian
Prairie.  By tonight, these two features should be in the process of
merging into one larger trough over the Plains.

As these two troughs advance, a surface cold front is progged to be
shifting southward out of Canada and into the Northern
Plains/northern Rockies late overnight.  Elsewhere, high pressure
will largely prevail, as the remnant baroclinic zone over Florida
and the northern Gulf of Mexico region weakens further.

Severe weather is not expected through the period, given the benign
pattern.  Showers and a few embedded thunderstorms are expected from
Florida westward across the Gulf to Texas, near the dissipating
front.  Showers and a few lightning strikes are also expected across
portions of the Rockies -- with greatest thunder risk apparent over
eastern Utah/western Colorado near the peak-heating position of the
center of the ejecting/weakening cut-off low.

..Goss/Gleason.. 10/18/2018

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SPC Oct 18, 2018 0600 UTC Day 2 Convective Outlook

SPC 0600Z Day 2 Outlook
      
Day 2 Outlook Image
Day 2 Convective Outlook  
NWS Storm Prediction Center Norman OK
1152 PM CDT Wed Oct 17 2018

Valid 191200Z - 201200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
A couple weak thunderstorms are possible Friday night across parts
of Mississippi and Alabama, and during the day over central Texas
and parts of Florida.

...Synopsis...
A shortwave trough will move eastward across the Midwest and phase
with a large-scale upper trough developing over the Great Lakes
providing substantial cooling aloft. Northwesterly flow at all
levels will then spread southeastward across central parts of the
CONUS, bringing a reinforcement of dry air. While a weak surface
trough will precede the upper trough amplification, little if any
convective instability will be present to support thunderstorms as
the front approached the Appalachians. The exception may be across
northern MS and AL toward Saturday morning, where the tail end of
the front will interact with a late northward advection of 60s F
dewpoints and minimal instability.

Elsewhere, weak warm advection above the stable boundary layer may
yield weak elevated instability over parts of central TX where
showers will persist, while daytime heating and a moist air mass
support a few deepening convective showers over FL.

...MAXIMUM RISK BY HAZARD...
Tornado:  <2%     - None
Wind:     <5%     - None
Hail:     <5%     - None

..Jewell.. 10/18/2018

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SPC Oct 18, 2018 0730 UTC Day 3 Severe Thunderstorm Outlook

SPC 0730Z Day 3 Outlook
      
Day 3 Outlook Image
Day 3 Convective Outlook  
NWS Storm Prediction Center Norman OK
1205 AM CDT Thu Oct 18 2018

Valid 201200Z - 211200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Isolated thunderstorms are possible Saturday evening from northwest
Arizona into southern Nevada and Utah, along the northern Gulf
Coast, and in the vicinity of Lakes Erie and Ontario.

...Synopsis...
A strongly cyclonic 100-140 kt mid to upper level jet will dive
southeastward across the Midwest and toward the Ohio Valley during
the day, with substantial cooling aloft across the Great Lakes. Cold
air aloft coupled with the relatively warm lakes may result in
low-topped thunderstorms from northeast Ohio into western New York
during the afternoon and evening.

To the south, an east-west oriented front will continue to push
south toward the northern Gulf Coast, where 65-70 F dewpoints will
exist supporting a few weak thunderstorms prior to the front moving
offshore.

To the west, a weak upper low will approach coastal central
California, with steep lapse rates aloft extending eastward toward
the Colorado river valley. Midlevel moisture will spread northwest
across Arizona and into the Great Basin during the evening, with
scattered thunderstorms expected. Small hail cannot be ruled out
with some of the cells due to cold air aloft and modest deep-layer
shear, but severe weather is not anticipated.

..Jewell.. 10/18/2018

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SPC Day 1 Fire Weather Outlook

SPC Day 1 Fire Weather Outlook
          
Day 1 Fire Weather Outlook Image
Day 1 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0138 AM CDT Thu Oct 18 2018

Valid 181200Z - 191200Z

...NO CRITICAL AREAS...

...Synopsis...
An upper low centered over UT early this morning will devolve into
an open trough as it becomes embedded in the mid/upper-level
westerlies across the northern/central Plains. Some gusty
northeasterly winds may occur in conjunction with lowered RH values
for mainly the mountains/passes of southern CA as high pressure over
the central Rockies and Great Basin supports a modest nocturnal
increase in the surface pressure gradient across this region near
the end of the period (early Friday morning). However, the marginal
forecast pressure gradient suggests elevated fire weather conditions
will probably remain too brief/isolated to justify an elevated area
for the last couple hours of the period.

..Gleason.. 10/18/2018

...Please see www.spc.noaa.gov/fire for graphic product...

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SPC Day 2 Fire Weather Outlook

SPC Day 2 Fire Weather Outlook
          
Day 2 Fire Weather Outlook Image
Day 2 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0138 AM CDT Thu Oct 18 2018

Valid 191200Z - 201200Z

...Synopsis...
A upper-level anti-cyclone is forecast to be centered over the
Pacific Northwest on Day 2/Friday, while a weak upper low remains
just off the coast of southern CA. Surface high pressure over Great
Basin and northern/central Rockies will foster offshore flow across
southern CA through the period.

...Portions of Southern CA...
The surface pressure gradient from LAX-TPH and LAX-DAG is forecast
to strengthen close to critical thresholds Friday morning, and
moderate to perhaps strong/gusty northeasterly winds are expected.
The best potential for locally critical-level winds appears to be
for the higher terrain of Ventura and Los Angeles counties, where
isolated sustained winds of 20-25 mph could occur, with some higher
gusts to 35-40 mph possible. Widespread 15-20 mph offshore flow
appears likely elsewhere in much of the lower terrain/valleys of
southern CA. Poor overnight RH recovery is expected from late
Thursday evening into Friday morning given the gradually
strengthening low-level flow and local downslope warming/drying
effects. As diurnal heating and mixing of the boundary layer occurs
Friday morning and afternoon, RH values will easily fall into the
10-15% range across most of coastal southern CA.

Some consideration was given to introducing a critical area for
parts of Ventura and Los Angeles counties, but the lack of stronger
mid to upper-level winds and the marginal forecast surface pressure
gradient both suggest a broad elevated delineation is appropriate
for now. A critical upgrade may be needed in a later update if the
forecast surface pressure gradient strengthens any further.

..Gleason.. 10/18/2018

...Please see www.spc.noaa.gov/fire for graphic product...

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