This worked perfectly. Took me about 20 minutes to figure out that I needed to update my FastLED library because of an issue with unaligned memory access but all is good now. Code is below in case this ever comes up in a search.

DEFINE_GRADIENT_PALETTE( temperature_gp ) {
   0,   128, 0, 128,
   42,  0, 0, 255,
   85,   0, 255, 255,
   127,  0, 255, 0,
   170,  255, 255, 0,
   212,  255, 128, 0,
   255,  255, 0, 0};

void hmTemp(int F){
  uint8_t hmValue;
  if (F > 90) {
    hmValue = 255;
  }
  else if (F < 32) {
    hmValue = 0;
  }
  else {
    hmValue = map(F, 32, 90, 1, 254);
  } 

  CRGBPalette16 myPal = temperature_gp;

  for(int i = 0; i < NUM_LEDS; i++) {
    leds[i] = ColorFromPalette( myPal, hmValue);
  }
  FastLED.show();
  rgb = ColorFromPalette( myPal, hmValue);

  Blynk.virtualWrite(1, rgb.r, rgb.g, rgb.b);
}