Severe Storm Outlook Narrative (AC)
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ACUS02 KWNS 270539
SPC AC 270538

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1238 AM CDT Fri Apr 27 2018

Valid 281200Z - 291200Z


Scattered daytime thunderstorms are expected across much of the
Rockies, with locally gusty winds possible. Other low-topped
thunderstorms are expected across much of eastern Pennsylvania, New
York, and northern New Jersey.

...Synopsis and Discussion...
An upper ridge will be centered over the Plains on Saturday, flanked
by upper lows across the Pacific Northwest and the Northeast. Low
pressure in association with the northeastern trough will weaken as
it moves eastward across NY and into New England, while a cold front
trails south into eastern PA and toward Chesapeake Bay by late
afternoon. To the west, strong heating will occur over the Rockies,
with cool temperatures aloft supporting daytime thunderstorms.

Daytime heating and cool temperatures at 700 mb will support weak
instability, but CAPE profiles will be limited in height to around
the 500 mb level where an inversion will exist. Relatively shallow
convection is expected along the cold front beginning around 18Z
over central NY and PA, then increasing during the afternoon as the
front nears the Hudson Valley and Delaware River. Much of the
deep-layer shear offered by the upper trough will be ineffective,
but some strong wind gusts cannot be ruled out with this convection,
even if lightning is limited.

Scattered diurnal storms will occur from the Bitterroots into
central MT southward across NM and perhaps into Far West Texas.
These storms will be largely driven by heating, although a deepening
low pressure trough across MT may help to organize a few storms
capable of strong wind gusts. Lapse rates will be very steep through
a deep layer, but shear profiles will be marginal for any severe

Tornado:  <2%     - None
Wind:     <5%     - None
Hail:     <5%     - None

..Jewell.. 04/27/2018

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