1:00 AM
Wednesday April 4, 2001: Once again the best chance for supercell thunderstorms will be on the higher terrain of n.e CO/w. NE/e. WY. As broad 35-45 kt southwest 500mb flow develops across most of the high plains. Good vertical wind shear profiles and modest capes due to upslope on the higher terrain will be sufficient for supercell thunderstorms and possibly a brief tornado or two. Once storms move into cooler air of west-central NE and western KS, the storms should weaken. Another area of interest will be along the triple point in southwest KS and the eastern OK panhandle. The cap may break over this area, in fact cap strength looks a bit weaker southward through the eastern panhandle into the low rolling plains of northwest TX. There is a slight chance that isolated storms may break the cap along the dryline. With CAPES of 2500-3000 J/KG and moderate vertical windshear, these isolated storm will atleast develop mid-level rotation and perhaps move right of the mean shear vector and intensify. It will probably take until evening before any isolated storms form from the tripple point south along the sfc dryline. Overall I think the tornado threat is quite low, but you may see some nice supercells over the higher terrain of n.e. CO/ e. WY /w. NE. It's far from a sure bet along the dryline due to strength of the CAP.
Thursday may be the best chase day this week? Southwest flow at 500 MB increases to 45-60 kts across much of the plains states as upper low slowly moves east across southern CA/northwest Mexico. The eta model shows weak sfc low developing over eastern NE with a cold front extending into northwest KS. A triple point will be located near Phillipsburg, KS with a dryline extending south-southwest across northwest OK into the TX PNHDL. Deep moisture will be in place east of dryline, northward into eastern NE and IA. Looks like three possible areas: One, east of weak sfc low over eastern NE which will move into western IA, and a second area from the triple point in northwest KS, southward across northwest OK and into the TX PNHDL. Given the good vertical windshear and moderate cape there should be isolated dryline supecells, some of which may produce tornadoes, as long as the CAP breaks. The complicating factor is that convergence along the dryline will weaken through the afternoon as sfc pressures fall across eastern NM and CO due to the southwestern upper low advecting east. If upslope flow can develop along and north of the cold front later in the day Thursday, storms may develop on the higher terrain of n.e. CO/e. WY/ w. NE/ even e. MT. These storms will have the best vertical windshear, but at this time I'm not too sure about the instability. I think there will be tornadoes somewhere!
Friday: The entire 500mb closed low lifts northeast into NM. Looks like a big munching squall line will form along the pacific front from southern SD south through north TX. Your best option may be to play north of sfc low over eastern WY and western SD. Upslope flow and good vertical winds shear profiles will be sufficient for supercells and perhaps a few tornadoes. A second option may be to play tail end charlie over north TX, but the squall line will most likely expand farther south through the day, I doubt if there will be a true anchor supercell but you never know. Third option is to play out ahead of squall line incase isolated storms form, but CAP will probably be too strong for isolated storms to form well east of sfc convergence along the pacific front. Overall I'm not very optimistic about Friday, but I would probably take my chances north of sfc low in upslope flow.