3/9 – Brittany’s “Subtle Changes” Thursday Evening Forecast
The upper level ridge axis that has been dominating the region over the past several days will weaken tomorrow as a progressive upper level trough passes through. The main result will be a largely zonal flow regime taking hold and remaining in place in the mid and upper levels through Saturday night. In the low levels, a weakening front will slide into the area tomorrow as the parent trough axis pulls quickly to the east. This front should reach the coast and dissipate Friday night. The main impact from this front will be a slightly drier airmass advecting in from the north, and the chance of widely scattered showers and possibly a low topped isolated thunderstorm developing ahead of the front late Friday morning into early Friday afternoon.
By Saturday, surface ridging will shift to the east of the area, and this will allow for return flow to redevelop across the area. Moisture advection will quickly take hold, and dewpoints will surge back into the 60s by Saturday night. Temperatures will also begin to warm, and highs will remain well above normal in the upper 70s and lower 80s. Cloud development will be largely suppressed as increased negative vorticity in the wake of the trough continues to provide some upper level subsidence.