...SEVERE WEATHER OUTLOOK... SEVERE STORM POTETENIAL AREAS, SPC FIRE OUTLOOK AND TORNADO, DAMAGING WIND PROBABILITY...

 

SPC STORM PREDICTION CENTER DAY 1 CONVECTIVE OUTLOOK

SPC AC 161540

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   1040 AM CDT Sat Oct 16 2021

   Valid 161630Z - 171200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS PARTS OF THE
   NORTHEAST STATES...

   ...SUMMARY...
   A couple tornadoes and scattered damaging winds are possible across
   portions of the Northeast States through early evening.

   ...Northeast...
   A high-shear/low-CAPE convective episode is expected to peak later
   this afternoon. A swath of frontal precip, predominately stratiform 
   with embedded higher-reflectivity cores and sporadic lightning
   flashes, is ongoing from northern NY southwest through central PA.
   Some breaks in downstream cloud coverage should result in somewhat
   more robust heating across the eastern PA/NJ area south. However,
   buoyancy in this regime will remain meager owing to weak mid-level
   lapse rates. Farther north, where deep-layer ascent will be
   stronger, greater boundary-layer heating will likely be confined to
   a corridor along the Upper Hudson to Champlain Valleys. This latter
   region should coincide with amplification of 850-700 mb wind field
   this afternoon, where enlarged low-level hodographs will foster an
   embedded tornado risk for a brief period later this afternoon.
   Otherwise, a thin, low-topped QLCS is expected to evolve
   east-northeastward offering a threat for scattered damaging winds
   from strong to locally severe gusts. These threats should wane after
   dusk as convection spreads across New England.

   ..Grams/Jirak.. 10/16/2021

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   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 2000Z
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SPC STORM PREDICTION CENTER FIRE OUTLOOK

FNUS21 KWNS 161545

FWDDY1



Day 1 Fire Weather Outlook  

NWS Storm Prediction Center Norman OK

1045 AM CDT Sat Oct 16 2021

 

Valid 161700Z - 171200Z

The previous forecast remains on track with no changes required.

Morning surface observations show elevated to locally critical

conditions ongoing with RH values in the teens and wind gusts

between 20-35 mph. Weak surface pressure falls are noted across

northern CA and southern OR, indicative of the influence of the

approach upper wave that will result in a cessation of the offshore

wind regime later this afternoon/tonight. Until then, elevated

conditions remain likely and will be most prevalent across northern

Los Angeles and Ventura counties. Forecast concerns regarding

north-central MT outlined in the previous discussion below remain

valid.



..Moore.. 10/16/2021



.PREV DISCUSSION... /ISSUED 1245 AM CDT Sat Oct 16 2021/



...Synopsis...

An upper-level ridge will continue to move eastward through the West

and into the Plains today. By the end of the period, cyclonic flow

aloft will return to the West Coast. At the surface, a broad

anticyclone will be situated within the Great Basin into the

southern Plains. The strength of the surface high will peak early in

the period.



...Southern California...

Elevated to briefly critical fire weather conditions are again

expected across much of the Transverse and Peninsular Ranges. A

similar offshore gradient, though most likely weaker, to Friday

morning can be expected this morning. The pressure gradient will

relax by the afternoon. Current surface observations in the region

continue to show widespread RH below 20% and most locations will not

significantly recover by morning. Winds of 15-20 mph will be most

prevalent with the typical wind-prone locations seeing higher

speeds. Those terrain-favored areas are also where critical

conditions may occur briefly during the early to mid morning.



...North-Central Montana...

Locally elevated conditions may occur in the lee of the Lewis Range

as a weak surface trough develops along with modest flow enhancement

aloft. Confidence in winds reaching 15-20 mph is relatively high,

but RH may remain above critical thresholds. A small area of

remaining dry fuels exists and could support fire growth should RH

fall to 20-25%.



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

SPC DAY TORNADO, DAMAGING WIND PROBABILITIES