1PM Day 3 Convective Outlook for Saturday, January 31. NO THUNDERSTORM AREAS FORECAST
SUMMARY
Thunderstorm probabilities across the U.S. for Saturday through Saturday night appear less than 10 percent.
Discussion
Models suggest that short waves within split flow across the eastern Pacific into western North America will remain progressive Saturday through Saturday night. This includes a large and vigorous, but slowly weakening, mid-level trough and associated surface cyclone within the primary belt of westerlies, which are forecast to approach coastal areas from Alaska into the Pacific Northwest.
While colder mid-level temperatures, potentially supportive of weak boundary-layer destabilization, are forecast to remain offshore, the leading edge of stronger mid-level height falls may begin spreading inland of the Pacific coast during the latter half of the period. It appears an evolving mid-level high in the southern mid-latitudes will be forced inland across southern California into the southern Great Basin, with a trailing cyclonic circulation approaching northern Baja. However, models indicate that amplified downstream mid-level ridging will be maintained through at least this period across the Canadian Rockies and adjacent Prairies into the northern U.S. Intermountain Region and Rockies.
Digging short waves to the lee of this ridge will reinforce large-scale troughing east of the Rockies through the U.S. Atlantic Seaboard. However, the most prominent perturbation within this regime is forecast to pivot across and offshore of the southern Atlantic Seaboard. As it does, it appears that a broad offshore surface low will undergo notable deepening.
While considerable spread remains evident in association with developments across and offshore of the Atlantic Seaboard, it appears that this may include at least a couple of areas of significant embedded cyclogenesis by late Saturday night. One cyclone may continue to deepen along a frontal zone northeast of the Bahamas, across and north/northeast of the Bermuda vicinity, with higher moisture content generally confined to areas along and southeast of this track.
Along a stronger baroclinic zone closer to the Carolina coast, it appears that a much more rapidly deepening and stronger, but similarly compact, cyclone may develop to the east of the coastal waters. However, within a cooler/drier environment, models suggest that any destabilization potentially supportive of thunderstorm development may be confined to areas well offshore, near the Gulf Stream.