Disclaimer:  This site is not affiliated with the National Hurricane Center, Hurricane Hunters, Storm Prediction Center, or National Weather Service.  ALL forecasts herein are the result of my analysis, (to which you will see me at times, insert excerpts from various agencies due to the nature of the importance of the information) and I am solely responsible for the content.  As ALWAYS, follow the National Hurricane Center, National Weather Service, and your local Emergency Management officials for emergency decisions.  In addition, this is strictly a FORECAST OFFICE.  I CANNOT make decisions regarding travel plans, etc.  My purpose, is to provide you the information, based solely on information I analyze, and the accuracy of the information at hand of the time of analysis, so you may make informed decisions.
(T. F. “Storm” Walsh)

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I will reiterate, my forecasts are based on the available information at the time of analysis, and are only as accurate as the information analyzed and the solutions provided.

Good day everyone!

As I’ve mentioned before, I continue to monitor for any severe weather threats on almost a day to day basis. 

The Storm Prediction Center (SPC) has issued a 30% probability (which would equate to a MODERATE risk outline) in the DAY5 Outlook from: East Texas into the Mid/Lower Mississippi Valley.
SPC DAY 5 SEVERE WEATHER PROBABILITY (IMAGE LINKED)

CSU – MLP DAY 5 FORECAST (CLICK FOR LARGER IMAGE)

The following is from the current SPC DAY 5 Outlook:

…DISCUSSION…
Medium-range guidance suggests that an initially zonal, intense mid/upper jet across the western into central mid-latitude Pacific may undergo considerable amplification into and through this period. It remains a bit unclear how emerging waves will impact the downstream pattern by the middle to latter portion of next week.

However, it still appears that one significant preceding short wave trough, migrating inland of the Pacific coast by early Monday, will progress into and across the southern Rockies, before accelerating east-northeastward through mid week. And guidance remains suggestive that this will be accompanied by strong surface cyclogenesis, perhaps most notably across portions of the east central Great Plains toward the lower Great Lakes region late Tuesday through Tuesday night. This may include an evolving warm sector with intensifying low-level and deep-layer shear (in the presence of southerly to southwesterly flow strengthening to 50-100 kt in the 850 to 500 mb layer), coincident with an influx of moistening and destabilizing boundary-layer air off the northwestern Gulf.

Spread typical at this extended time frame (day 5) lingers among the various model output concerning the sub-synoptic, and even synoptic, details across the southeastern Great Plains through Ohio Valley and Southeast, which may considerably impact the severe weather risk area and potential. However, the medium-range guidance depicts an environment at least conditionally supportive of an organized severe weather event, including potential for a few strong tornadoes and damaging straight line winds.

It is possible, but perhaps a bit more uncertain, that this could continue across parts of the southern and middle Atlantic Seaboard on Wednesday.

The following were the forecast parameters and indices analyzed this afternoon, with the maximum values pertaining to the SPC 30% outline mainly from the central portion, South.  Based on my analysis of the indices and parameters, ALL severe threats should be probable.  While a couple of indices are below the threshold (again, I expect more solid information when the NAM is within forecast range), deep layer shear, moderately steep mid level lapse rates, moderate lifted indices, SWEAT Index, and EHI values indicate a decent tornado threat, some of which could attain EF2 – EF3 strength.  I’m making a change to the EHI values posted.  I have been averaging the minimum and maximum values and coming up with the “average” for each.  Beginning today, values will be posted with the range for the minimum and maximum values.  In regards to this synopsis, the minimum values will represent indices within the 15% outline, and maximum values within the 30% outline.  Bear in mind, indices recorded below are for the time of peak intensity which is currently unknown due to the various models analyzed still showing discrepancies among themselves in regard to forecast strength and timing.  However, the majority of indices do indicate a MODERATELY unstable environment in the forecast.   Indices were derived and are a combination from the CIPS DETERMINISTIC model, GFS, ECMWF and CMC models, as the NAM 3 km model I routinely use only goes out 60 – 84 hours in the forecast period.  Based on this, forecast indices should be considered somewhat of low confidence at this time.  Once the NAM comes into play, I should have more accurate information on these indices for Monday’s forecast.  Some indices meanings are posted below, and the NWS page containing a more extensive list can be accessed further on in the synopsis:
SBCAPE: 500 – 1500 j/kg-1
MLCAPE: 250 – 750 j/kg-1
MUCAPE: 500 – 1250 j/kg-1
SRH 0 -1 km: 200 – 400 m2/s2
SRH 0 -3 km: 300 – 500 m2/s2
SRH EFFECTIVE: 250 – 500 m2/s2
L. I.: -1 to -5
SCP: 2 – 12
STP: 1.0 – 2.0
0 -6 km SHEAR: 60 kts- 70 kts
EFF. SHEAR: 45 kts – 55 kts
MID LEVEL LAPSE RATE: 7.5C – 8.0C
DEWPOINT: 60F – 68F
EHI (MINIMUM): 0.5 – 0.8 EHI (MAXIMUM): 1.4 – 2.3
TOTAL TOTALS INDEX: 48C
K INDEX: 32C – 34C
SWEAT INDEX: 525 – 540
THOMPSON INDEX: 33 – 39
CRAVEN – BROOKS INDEX: 10,000 – 20,000

CAPE

ENERGY HELICITY INDEX

K INDEX

TOTAL TOTALS INDEX

STORM RELATIVE HELICITY

LIFTED INDEX

SWEAT VALUES

THOMPSON INDEX

Craven SigSvr Parameter:
The simple product of 100mb MLCAPE and 0-6km magnitude of the vector difference (m/s; often referred to as “deep layer shear”) accounts for the compensation between instability and shear magnitude. Using a database of about 60,000 soundings, the majority of significant severe events (2+ inch hail, 65+ knot winds, F2+ tornadoes) occur when the product exceeds 20,000 m3/s3.
A little fact on SRH values and tornadoes from NOAA / NWS.

Again, for the time being, this should be considered a somewhat low confidence forecast.  I will continue to monitor all of this over the next few days for any changes to the forecast instability, and will try to update daily except Sunday.

The SPC has also issued a 15% probability (which would equate to a SLIGHT risk outline) in the DAY 6 Outlook for: Most of the Eastern Seaboard
SPC DAY 6 SEVERE WEATHER PROBABILITY

The following NWS Watch / Warning map will provide local NWS information for your area.  Click the image, then once it refreshes, click on your area of interest to view any special weather statements, hazards or advisories for your area.
NWS WATCH / WARNING DISPLAY (LINKED…CLICK MAP, THEN YOUR AREA)

NWS DOPPLER RADAR LOOP (LINKED, CLICK RADAR MAP)

RAP RADAR (CLICK IMAGE THEN GO TO LOOP DURATION AND PICK LENGTH OF LOOP, THEN CLICK RADAR SITE)
CARIBBEAN RADAR (CLICK IMAGE TO ACCESS ANIMATION)

You may direct any questions by contacting me personally, ANYTIME, at: [email protected]

Have a blessed day!

T. F. “STORM” WALSH III
GMCS, USCG (ret)
METEOROLOGIST / HURRICANE SPECIALIST /SEVERE WEATHER SPECIALIST