Part I: Medium Range Forecast Exercise for Tallahassee, Florida

Medium Range Forecast Exercise for Tallahassee, Florida:
A Prototype for Forecasting along the Gulf Coast in Fall

Part I, Section 4: Day-5 Forecast for Tallahassee

Now, consider a possible day-5 forecast for Tallahassee, Florida (TLH) after examination of forecast guidance based on initial conditions at 0000 UTC 23 October 2003. We duplicate Table 2 below for your convenience. Also, consider the TLH Zone Forecast Product for day 5 below:

ZONE FORECASTS
NATIONAL WEATHER SERVICE
TALLAHASSEE FL THU OCT 23 2004

FLZ013>019-026-027-242300-
CALHOUN-FRANKLIN-GADSDEN-GULF-JEFFERSON-LEON-LIBERTY-MADISON-WAKULLA-
INCLUDING THE CITIES OF...APALACHICOLA...BLOUNTSTOWN...BRISTOL...
CRAWFORDVILLE...MADISON...MONTICELLO...PORT ST. JOE...QUINCY...
TALLAHASSEE

4:00 am EST, 23 October: Day 5 -
.TUESDAY...PARTLY CLOUDY, LOWS IN THE LOWER 40S, HIGHS IN THE LOWER 70'S

10:27 am EST, 23 October: No change in Day 5 forecast

4:00 pm EST, 23 October: Day 5 -
.TUESDAY...MOSTLY CLEAR, LOWS IN THE LOWER 40'S, HIGHS IN THE UPPER 60'S

Table 2: Day-5 MRF MEX MOS for TLH valid 28 October 2003

Parameter

12 UTC 28 October 2003

00 UTC 29 October 2003

X/N

TMP

DPT

CLD

WND

P12

P24

Q12

Q24

Write your forecast in the window below. Caution: When you close this window, the text will be lost.

Now, consider the following question.

Question I, Part I, Section 4

Think about it. To what extent does your forecast for TLH for 28 October 2003 (day-5) agree with the day-5 TLH ZFP’s for that date? Maximum temperature? Minimum temperature? Cloud cover?

When you are done, click on view discussion. There are no right or wrong answers for this question

Discussion Your forecast will depend on the extent to which you believe the GFS solution and its associated GFS MEX MOS product. The TLH ZFP’s from 23 October 2003 are largely consistent with this input, forecasting partly cloudy to clear skies and temperatures that are below the climatological mean for the date. The ZFP temperatures are adjusted upward from the MOS product by about 5° (5 p.m. update), making the forecasted temperatures for the day around 9° below normal. This adjustment is in agreement with the practice of trending longer range forecasts toward the climatological mean. All in all, the ZFP’s look to be a very good forecast for 28 October 2003, assuming the GFS verifies.

If the upper air flow pattern does not evolve in a manner consistent with the GFS 120-hour forecast of a major full latitude longwave trough over the eastern U.S., then the forecast of clear, cool, dry conditions for TLH may be in jeopardy. In particular, if the UKMET 72-hour forecast of significant vorticity digging into Texas persists into 28 October 2003, then TLH may experience much milder temperatures and greater cloud cover. If the residual moisture from Patricia does indeed propagate northeastward into the Gulf Coast region as suggested by the UKMET solution, TLH may receive significant rainfall, as well. (See the loops for the GFS and UKMET forecasts in Part I, Section 2.)

Medium Range Forecast Exercise for Tallahassee, Florida: A Prototype for Forecasting along the Gulf Coast in Fall

Question I, Part I, Section 4

Medium Range Forecast Exercise for Tallahassee, Florida:
A Prototype for Forecasting along the Gulf Coast in Fall