Day 4-8 Outlook
Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0317 AM CST Mon Feb 01 2021 Valid 041200Z - 091200Z ...DISCUSSION... Recent medium-range guidance is showing better consistency into the weekend. Current expectation is for an upper trough to extend from the Canadian Prairie Provinces to off the southern CA coast early D4/Thursday. This upper trough is forecast to move eastward on D4/Thursday and D5/Friday. The northern and central portions of the trough will be more progressive than the southern portion, which may lead to bifurcation and the development of a upper low off the northern + coast of the Baja Peninsula. Surface low associated to the primary trough is expected to move from the central Plains northeastward across the MS Valley and upper Great Lakes and into Ontario by D5/Friday. Attendant cold front will sweep eastward/southeast across the southern Plains and mid/lower MS Valley on D4/Thursday and remainder of the eastern CONUS on D5/Friday. Modest low-level moisture will precede this front, but relatively cool and cloudy antecedent conditions are currently expected to limit thunderstorm coverage. Slight changes in the thermodynamics would result in a more favorable environment and trends will be monitored closely in subsequent outlooks. Another shortwave trough and attendant surge of cold air is forecast to follow quickly in the wake of the first system this weekend. Short period between this surge and the lead wave is expected to limit moisture return and thunderstorm potential.
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