Thursday, June 14, 2018

Moisture With Dying Bud Pushing Slowly North

Mid-level buildups at sunrise this morning (with passing dove). The morning skewT for TWC sounding launched from campus (below) indicates the cloud layer nicely. Sounding remains fairly dry, especially in very deep, residual boundary layer. There may be a sliver of CAPE this afternoon from about 550 mb to around 300 mb. Temperatures in this layer appear favorable for graupel and lightning, but it is not clear whether there could be enough CAPE or vertical velocity for thunderstorms locally. The plot of detected CGs for 12-hours ending at 06 UTC last night (second below from Atmo and Vaisala) indicates thunderstorms east and south of Tucson yesterday and these should edge closer today.

TS Bud continues to weaken as it moves slowly northward. The IR image above is from 1330 UTC this morning and little deep convection remains, except for band north to northeast of storm center. The morning track forecast from NHC is shown below. The remains of Bud (which is forecast to dissipate in 72-hours or sooner) come ashore near Guaymas, Mexico after crossing southern Baja.

Even though remains of Bud appear to be veering off toward northeast and weakening rapidly, all the model forecasts have trended wetter for our area in last night's forecast runs - so a mixed bag of signals this morning. Above is again from SREF plumes at SPC page - only a few members forecast an inch or more at airport, while several forecast very light amounts. The ensemble mean is a bit over half an inch. Note that the member forecasts also show a very large time window across which the main event is forecast to occur - from the 15th to a couple of models which forecast main precipitation event on Sunday. Shown below is the 06 UTC WRF-GFS forecast from Atmo last night - model continues to forecast very significant mid-June event for all of eastern Arizona.

There are a number of uncertainties here and forecast for the metro area remains very difficult - will watch with interest to see how this all evolves.

No comments:

Post a Comment