Wednesday, July 30, 2014

Unusual Situation Continues

Yesterday the PW did drop during the afternoon as per the early WRF forecasts, but not as low as model had indicated. Five day time-series of GPS PW near NWS Office on campus above shows that values have held between 1.25 and 1.60 inches through the period. The CAPE by 00 UTC yesterday was gone and during day thunderstorms stuck to higher elevations as per CG flash locations through midnight last night - below. Several storms in southeast Arizona did produce some decent rain amounts due to their slow movement - MesoWest rainfall second below for 24 hours ending at 7 am MST this morning.

The strange 500 mb pattern continues with northern and southern circulation centers within the large ridge over the West. Westerly winds across central part of West dominate between the two anticyclone centers. The forecast above for 500 mb is valid at 00 UTC on 1 August and is from this morning's NAM forecast cycle. As the trough over eastern portion of country deepens, the ridge is displaced westward and the forecast indicates the anticyclone centers shift to southwest Arizona and Idaho. This is certainly not a very good pattern for southeast Arizona - unless the low-latitude disturbance off Baja would trigger a significant increase in PW into the Southwest.

July here at the house has been very dismal, in spite of the early onset of storms. Looks like this may be the 4th driest July here during the past 15 years.

No comments:

Post a Comment