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My opinion on SPC day 3

Posted: Fri Apr 30, 2004 8:38 pm
by Allexpert Mike
SR for SE-MA.......think they should of held off.

BL-6km shear profiles aka vertical shear profiles will be descent but strongest wind fields will remin post forntal. If that 120KT jet streak wasn't behind the front we could see damn good BL-6km shear profiles. Deep layer shear will still be strong and be supportive for updraft strength between 45-55KTS. The only killer is the WEAK instability which may be the reason for no storms to reach severe standards with SBCAPE generally around 500j/kg. In addition thermal ridge over and to the east of the moisture tongue will limit threat, eventhough H8 dew points 10-12C pretty impressive. Ample low level moisture with descent shear profiles will combine for marginally severe hail and flash flooding with mid level flow parallel to the front creating threat for training.......in addition with a relatively stable BL above NJ any storms north of there should be elevated.

SPC banking on diurnal heating to raise the instabiltiy to marginal limiits,,,,,but looking at latest data,,,clouds roll in pretty fast but looks like sunshine could peak thorugh during early PM hours but its loooking iffy now

Posted: Fri Apr 30, 2004 9:07 pm
by USAwx1
Mid level (700-500mb) lapse rates arent that impressive either. Generally LESS than 6.00 DEG C/km. Combination of weak CAPE and SRH should only yield EHI indices of generally 1.0 or less by later in the afternoon ahead of the SFC boundary between 18-21z (refer to latest 0z MESOETA) with the highest values confined to eastern MD, SE PA, the Delmarva and SRN NJ.

Posted: Sat May 01, 2004 11:08 am
by Colin
I think it'll be mainly a shower/garden-variety thunderstorm type of day...don't see any big instability in the area, and any stronger thunderstorms should be confined to the southern Delmarva area, if anywhere.

Although heavy rain may become a problem.