Quick update 07_06_2023

 Overview:

Some significant differences exist in the Medium Range Guidance (days 3-10) on the amount of moisture/convection expected to make it into southern Arizona. The difference appears to be related to the handling of the developing tropical cyclone in the Eastern Pacific.

QPF:

GFS: The GFS is somewhat more aggressive in the 5 -Day QPF with 2+ inch amounts into Santa Cruz and parts of Cochis Counties and 0.5" amounts extending towards the greater Tucson area. 
ECMWF: Heavier accumulations stay south of the border with only isolated amounts of .10-.25" 


These differences appear related to how much more intense the tropical cyclone development is in the GFS. This leads to a significantly more intense moisture surge up the Gulf of California into Arizona.


GFS

ECMWF

The GFS strengthens the Tropical Cyclone to a central pressure of less than 990 hPa, while the ECMWF keeps pressures above 1000 hPa, leading to higher dewpoint values in Southern AZ. We'll have to wait and see which scenario pans out. Once the Hurricane specific models are initialized, it'll give us more information.






Comments

Post a Comment

Popular posts from this blog

May 16th, 2024: Chances for Elevated Convection Today

Image
  Synopsis A closed low over New Mexico will promote a chance for elevated showers and thunderstorms across the eastern half of AZ through this evening. A dry sub cloud layer will prevent any significant rainfall accumulations, and the primary impacts will be occasional lightning strikes, gusty winds, and blowing dust.   Current Conditions At 9:45AM MST, visible satellite imagery displayed a weak, small cluster of elevated showers and isolated thunderstorms in the Phoenix vicinity moving rapidly southeastward. Visible satellite imagery loop overlaid with GLM flashes this morning courtesy of College of Dupage. SPC 500mb analysis this morning showed a weak closed low over Central New Mexico, and a subtle shortwave on the backside of the low over AZ.  SPC 500mb analysis as of 17z this morning. The region of convection near Phoenix this morning is associated with PVA ahead of the subtle shortwave.  This mornings 12z TUS sounding measured a relatively dry and st...
Read more

Aug 12th - Quiet Sunday with increasing moisture and activity on Monday

Image
  Overview: Moisture levels have decreased since yesterday which should keep instability in check for most of the greater Tucson area. Convection today should largely be limited to an axis of higher precipitable water situated from southwest to northeast across central Pima County. Some convection is also possible along the higher terrain to the northeast of Tucson. Moisture levels should increase tomorrow as the upper-level low over California shift westward allowing the upper-level ridge to build back into New Mexico. This should shift the 500 hPa flow over southeastern Arizona from southwesterly to southeasterly, allowing for some moisture advection into the region from Mexico. Additionally, upper-level disturbances embedded in the southeasterly flow could enhance convective coverage, although the timing of these disturbances relative to peak heating times may be an issue. Today: The sounding from Tucson is unavailable this morning so I will be referencing the sounding from...
Read more

March 24th, 2024: Windy, Cold, and Showery Sunday

Image
  Synopsis The primary vort max and associated cold front has moved east into New Mexico this morning leaving behind a cold and marginally unstable airmass across AZ. Enough instability will remain in place through this evening for scattered convective showers and an isolated thunderstorm or two across the state. Additional rainfall and snowfall amounts will be highly variable and dependent on trajectory of showers. Expect anywhere between a trace to 0.25 inch of rainfall in the valleys with between 0.10 and 0.50 inches over the higher terrain. Snow levels will remain above 5000 feet with anywhere between a dusting to 6 inches of additional snowfall in the mountains. Current Conditions   Visible satellite imagery and GLM data indicating scattered convective showers and isolated thunderstorms across AZ this morning. GOES-16 visible satellite imagery overlaid with GLM flashes at 9:00AM MST courtesy of College of Dupage. The vort max which provided AZ with moderate to h...
Read more