:: M is for _____?
Monsoon? Minnesota? Maybe? All these words fit, however monsoon and Minnesota don't seem to fit necessarily together. But the southwesterly monsoonal flow we are under the influence of is filling skies above with ingredients for another round of soaking showers and thunderstorms. As discussed yesterday, high pressure over the Lone Star State is serving as a pump for monsoonal moisture and heat from the desert southwest (incendentally, AZ and NM have been experiencing their seasonal monsoonal rains as well, with a meandering low pressure system that keeps drifring like an eddy between the Grand Canyon and the Rio Grande). The same moisture fueling the desert rains is riding a conveyor belt of air flow up to the Great Plains. Zonal (west-to-east) upper level flow skipping over the Rockies produced typical lee-side low pressure east of the Front Range and the instability kicked up a nice MCS that pushed from NE to IA ovenight. The southwestern low level flow spilled some of the MCS's precip northeastward into Lakeville this AM in the form of showers. This will only add to the ingredient batch for today/tonight as MN's turn for heavy convection returns...
A strong low pressure system is formed near Medicine Hat, AB last night and is digging in to the plains along the Canadian border. An associated surface cold front is in genesis, and by late afternoon the system will be on track for a positive orientation from TVF to ABR, as discuessed yesterday. Ahead of the front will be warm moist monsoonal air pooled up over MN. Couple the cyclonic/frontal system with a nice zonal jet max in the upper atmostphere, and the monsoonal jet max in the lower levels, converging somewhere between FAR and FFM this afternoon, and a nice profile triple-point sets up in the atmosphere. Models from the 12Z run are a little at odds on this feature, however, and timing is a little off as well. Later models and the RUC outputs may be able to clarify, as well as some RAOB data, but for now, local NWS WFO's are excited about supercells, and the SPC has issued a Public Info Statement regarding the potential.
My expectations are guarded for now, but a betting man will favor some typical behaviors...like storm intiation over the Couteau de Praries, and then firing along the frontal boundary from there. From 6pm to 10pm the Twin Cities will be under the gun, with storms arriving at or just after mature stage, some in supercells or possibly a bow MCS or even derecho. These are all possible with todays setup...especially since models are pointing out max CAPE and theta-E values right over us at 00Z.
Updates may be warranted later today as details evolve...but for now, here is your friendly neighborhood forecast:
SATURDAY... Partly Cloudy, High 87. SSE winds 10-15 mph. 70% chance of showers and thunderstorms after 6pm. Some may be heavy to severe with torrential rains and damaging winds or hail. STAY TUNED TO LOCAL NEWS RADIO OR TV FOR WEATHER ADVISORIES. Storms ending after midnight. Low 67.
SUNDAY...Partly Cloudy and a slight chance of a lingering shower in the AM, then clearing and sunny. High 82. West winds turning NNW 5-10 by afternoon. Low 60.
MONDAY...Clear Skies and 84.