Suddenly: Pressure: 29.74 in / 1007.0 hPa

[dixiebreeze]

Anyone know why our BP suddenly dropped to 29.74 tonight (west central Florida) after days of 29.9 to 30 + levels?

[cpdaman]

ya might have something to do with the thread i started about low west of tampa

but no mention in 930 disc

[JonathanBelles]

Ive got a pressure of 29.98 here.

[wobblehead]

Look at current buoy reports specifically the pressure tendancy report and compare eastern gulf to the east coast of Florida. Then look at todays 12z CMC run of MSLP. This will tell you whats going on.

[NEXRAD]

Since this pressure happened on Monday, the current reports (which show little, if any anomalies) may not be relevant.

I'd lean towards a convective explanation. While I fail to recall what t'storm activity was happening on Monday, sometimes a cluster of strong or severe cells can leave a remnant low called a wake low. Such lows can drastically alter surface pressures, albeit are typically short-lived. Alternatively, pressure fluctuations will happen before and after significant convective boundary passage to include t'storm passage. I've observed noticeable barometric pressure changes before and after tropical squall bands, for instance. Likewise, I've seen more subtle pressure changes before and after a summer t'storm passage.

Those are my ventured guesses. It may also have something to do with the frontal boundary that was hung-up over Florida over the weekend. Finally, if the pressure was an isolated report, it may simply be a faulty barometer. Those definitely happen.

Jay
KSC FL

[wobblehead]

Good point NEXRAD. The data I refered to illustrated the fact that the western periphery of the BH was over the Fl peninsula as shown by lower mslp buoy readings in the eastern gulf than from buoys off the Fl Atlantic coast.

[wjs3]

I like Nexrad's convective explanation. Here's the radar from 23Z on the 23rd...I think that's a relevant time?

http://www.ral.ucar.edu/weather/radar/d ... duration=0

WJS3

[stormchazer]

My station ran 29.9 all day yesterday.

[hurricanefloyd5]

I hope something forms soon???

[NEXRAD]

Thanks for the archived link, WJS3.

From the stand alone image, I'd estimate that there's a boundary situated from about Brooksville NE to Lake George (near Astor/Astor Park in Nrn Lake Co.) and then NE more towards the Flagler-St. Johns County line. If the boundary were southbound, which is fairly likely, then Crystal River area would have been just behind the boundary when the pressures fell. With high pressure to the south of Florida and lower pressures to the north, some degree of fall is plausible. I won't suggest that's a definitive explanation, of course.

Alternatively, if the pressure falls were not observed at Crystal River, but were across "West Central Florida" in general, then I'd suggest a slight possibility of a short-lived wake low. The radar image appears to show a possible meso low around Dade City (in eastern Pasco County). Without a radar loop, however, such a feature is impossible to readily discern. If anyone has the station reports from that time frame, it'd be easy to plot out the data and see whether any patterns are present. The pressure and wind patterns might show whether there was a boundary, some sort of a surface low, or other localized feature.

Jay
KSC FL

[hurricanefloyd5]

Nice!!!!!!!!!!

[wjs3]

Thanks for the archived link, WJS3.

From the stand alone image, I'd estimate that there's a boundary situated from about Brooksville NE to Lake George (near Astor/Astor Park in Nrn Lake Co.) and then NE more towards the Flagler-St. Johns County line. If the boundary were southbound, which is fairly likely, then Crystal River area would have been just behind the boundary when the pressures fell. With high pressure to the south of Florida and lower pressures to the north, some degree of fall is plausible. I won't suggest that's a definitive explanation, of course.

Alternatively, if the pressure falls were not observed at Crystal River, but were across "West Central Florida" in general, then I'd suggest a slight possibility of a short-lived wake low. The radar image appears to show a possible meso low around Dade City (in eastern Pasco County). Without a radar loop, however, such a feature is impossible to readily discern. If anyone has the station reports from that time frame, it'd be easy to plot out the data and see whether any patterns are present. The pressure and wind patterns might show whether there was a boundary, some sort of a surface low, or other localized feature.

Jay
KSC FL

Jay:

I don't know the geography well enough to follow what you are saying, but the concepts seem plausible to me, with the MCS readily apparent on the radar.

If you (or anyone else) wants to get archived...er...Nexrad images, they are available at NCAR (among other places) for a few days (longer than that, you need to go to NCDC, but that gets more complicated). Right now from the 21st on is available:

http://www.ral.ucar.edu/weather/radar/

And you can go ahead and do a loop using the controls on the top right. If you can get archived obs to combine with this, we can probably analyze it.

WJS3

[NEXRAD]

Thank you for that info., WJS3. I'll take a look this afternoon/evening if I get a chance.

A quick morning thought... there was an unusually strong wake low that plowed across West Central Florida awhile back. I thought it was the "Christmas 2004" storm, but alas that was a strong frontal low. Instead, the potent wake low hit on the morning of 12 April 2004 (see NCDC event description per KTBW below). It seems that 2004 was truly the year for Florida to have unusual weather episodes of all sorts.

http://www4.ncdc.noaa.gov/cgi-win/wwcgi ... ent~528736

- Jay
KSC FL

[wjs3]

cool. Thanks for the link. I look forward to your analysis and further discussion. Meso is not a strength of mine and I would love to work on it.

WJS3

[jdray]

That shows the energy in the atmosphere quite nicely, considering that its been 30.20 on average past few days here in NE Florida.

Lots of energy, hence all of the waterspouts and tornadoes lately.

I wish the front would move.

[kevin]

Its a hurricane forming Dixie.