Uh-Oh M-5 2011 Houston Marathon Weather Forecasts

Yesterday afternoon, the forecasts all had significant rises in predicted temperatures for Sunday. The GFS model is looking pretty bad (at least for a cold-weather person like me) with dewpoints at and above 60°F. Fortunately we shouldn't see extremely high dewpoints because water temperatures in the near-Gulf are in the 50s now and shouldn't heat up much during the week with more cool weather. But if the dewpoint is near 60°F Sunday, I'll need to slow my pace by at least 10 to 15 seconds per mile. Today's NWS discussion still has high uncertainty for Marathon Sunday:

FLAT/BRIEF RIDGE TO PREVAIL TONIGHT/WEDS WITH A REINFORCING COLD FRONT THURS TO KEEP TEMPS AOA SEASONAL NORMS FOR THE REST OF THE WEEK. NO SIG-NIFICANT POPS WITH THIS FROPA AS MOISTURE WILL REMAIN LOW WITH NO ONSHORE WINDS IN THE INTERIM. HOWEVER THINGS PROGGED TO CHANGE BY THE WEEKEND AS ANOTHER UPPER LEVEL CLOSED LOW DEVELOPS AOA THE CA BAJA. THIS SHOULD RESULT IN INCREASING W/SWLY WINDS ALOFT AS FLOW AT THE SFC LOOKS TO DRAW A GREAT DEAL OF MOISTURE IN OFF THE GULF. SOME DISCREPANCIES NOTED WITH THE TIMING OF THIS SYSTEM IN THE EX-TENDED WITH ECMWF RUNNING SLIGHTLY SLOWER THAN GFSLR AT THIS TIME. WILL LEAN MORE TO A SLOWER TIMING AS THESE SYSTEMS ARE OFTEN WONT TO DO.

The hourly weather forecast shows decent temperatures up until about 9AM. At start time it's showing 51°F with the winds south at 7 mph, but 10AM shows temperature and dewpoint at 60°F with the south wind up to 10 mph. Five days out, you can't rely on an hour!

The 7.5-day model includes marathon morning [the graph is in UTC, six hours ahead of Houston] the temperature near 60°F, rain and a wind shift from a south wind to a northwest wind. The text version of the MRF model. shows a low of 56°F and wind at 9 mph in the morning.




The Weather Channel tends to weight their long term predictions with seasonal averages. For Saturday night they show:
Overnight Low 53°F
Precip 40%
Wind: SSE 4 mph
Max. Humidity: 82%
Showers


For Sunday they show:
High 67°F
Precip 30%
Wind: SSE 7 mph
Max. Humidity: 82%
UV Index: 4 Moderate
Sunrise: 7:13 AM CT
Few Showers


AccuWeather has Saturday night and Sunday on their 6 to 10 day forecast. They predict a much stronger cold front:

Saturday Night, Jan 29
Low: 53°F RealFeel®: 51°F
Cloudy most of the time with a couple of showers
Winds SSW at 13 mph with gusts to 21

Sunday, Jan 30
High: 63°F RealFeel®: 62°F
Mostly Cloudy
Winds NW at 10 mph with gusts to 16